Boreal Songbird Initiative - Please help!

The Boreal Songbird Initiative, along with other environmental groups like Bird Studies Canada, Nature Canada, the David Suzuki Foundation, among others created a petition called “Save our Boreal Birds” a little over a year ago. This petition will be sent to the Prime Minister of Canada and many provincial leaders, and asks that vital bird habitat be kept intact despite the fact that over 30% of the Boreal Forest has already been designated for development. Many migratory birds that travel through the US and other countries breed in the Boreal Forest to the north.

Sign the petition at SaveOurBorealBirds.org to protect Canada's Boreal Forest on behalf of the billions of birds that breed there!

For the Birds - Common Grackle

Chances are good that Common Grackles have returned to your neighborhood by now. These large members of the blackbird family are one of the first of our migratory breeding birds to come back to Maine.

With a sleek, glossy black plumage and a yellow eye, the adult Common Grackle is a striking bird. The birds are about 12 inches long, including the long tail. It is not easy to tell males from females although the head of males, in favorable light, has a glossy purple head and breast. The female is usually slightly smaller than the male. In flight, grackles hold their tails in a V, like the keel of a boat.

Despite their sleek appearance, grackles will win no contests for the beauty of their songs. Both males and females sing the same harsh, squeaky song that some ornithologists interpret as "squ-eek", “readle-eak” or "scuda-leek". Some people think the song sounds like the opening of a gate with a rusty hinge. These birds also give a characteristic raspy "chack" call, often in flight.

Males sing more frequently than females and male song rates are highest early in the breeding season. Any individual sings a single song but there is a lot of variation among individuals. The songs therefore seem to be useful for individual identification.

Grackles are habitat generalists. Suburban areas, farmlands, swamps, and orchards are all suitable. Favoring more open habitats, grackles are typically not found in deep forests. Before European settlement and the clearing of forests, Common Grackles were uncommon birds in New England; now they are abundant. Aided by the planting of shelterbelts, Common Grackles have expanded their range westward across the Great Plains.

This species is highly gregarious; if you see one, you will probably see 10. Except for females incubating eggs, grackles roost together at night in noisy roosts, sometimes more than 100 birds in one roost.

Unlike some of our long-distance migrants, Common Grackles do not winter very far to the south of us. Some winter in southern New England with more wintering from Pennsylvania south.

Once the grackles return, keep an eye out for their courtship displays. The male will raise the feathers around his neck, drop his wings and sing his song for a prospective mate. This behavior is called the song spread.

Pairs form soon after the birds arrive. The female builds the nest, usually well above the ground in a conifer. The male guards the female throughout the nest construction process. Once the nest is complete, the female will perform a wing quivering display, a signal that she is ready to mate.

The male aggressively keeps other males away from his mate. A common threat display is sky pointing, when the male raises his bill vertically. This behavior is given by one male on the approach of another male. The display usually results in one of the males departing.

Common Grackles may nest alone but more often in colonies of ten or more pairs in tall trees, especially evergreens. Sometimes, nests are made in freshwater marshes, old building and even the lower parts of Osprey nests. The nest is made of twigs and grass stems. Most nests contain 5-6 eggs, which the female incubates for about 14 days before hatching. The newly hatched birds are ready for their first flight in 14-16 days. Unlike their dark parents, juveniles are dark brown with brown eyes.

Grackles have a broad diet, although insects are the most commonly captured prey. Grackles often search for food on the ground, walking slowly and deliberately. Occasionally, a bird may run and leap into the air to catch an insect. Grackles may probe in the ground for earthworms and will even take them from robins. Grackles will also search for food in trees. Besides insects, grackles are known to eat spiders, snakes, lizards and mice. The eggs and nestlings of other birds are not safe from grackles. Grackles are even reported to wade belly deep in freshwater for crayfishes, minnows, frogs and salamanders. Grackles will eat seeds including corn, acorns, and seeds of various weeds. In fact, Common Grackles are now a major agricultural pest, causing millions of dollars of damage to sprouting corn.

Some Common Grackles attain impressive ages. The oldest known Common Grackle was banded in Michigan and recaptured 20 years and 11 months later in Illinois! A Common Grackle in Minnesota lived to be at least 17 years old while a New Jersey bird lived to be at least 16 years and 1 month old. The average life span is likely much less than these extremes.

[Originally published on April 4, 2009]

For the Birds - Geo-locating and Bird Migration

Keeping track of bird migration is a time-honored practice of naturalists dating back over 200 years. All of us delight at the arrival of the first Red-winged Blackbirds, Hermit Thrushes, or Yellow Warbler in the spring.

Until recently, our understanding of the timing of bird migration was based on populations of birds rather than individuals. We have to be able to follow individual birds to truly understand migration speeds and routes.

Bird banding has contributed some useful information. However, the chance of a bird bander capturing a bird banded earlier in the migration is pretty slim. The chance of capturing a banded bird immediately after its arrival is slimmer yet.

Outfitting birds with radio-tags that emit unique frequencies provides a way to track individual birds. The range of most radio-tags is limited to a couple of miles so this technology is more useful for tracking the movements of resident birds.

More recently, satellite transmitters have been developed that allow ornithologists to monitor the position of birds from their computers. For instance, researchers used satellite transmitters to track the migration of Short-tailed Albatrosses across the Pacific Ocean (http://www.wfu.edu/biology/albatross/shorttail/shorttail.htm).

Although radio and satellite transmitters have been miniaturized, they are still too large to place on most songbirds. A new technology, called geo-locating, promises to provide new insight into the pace and direction of small bird migration.

The geo-locaters were engineered by members of the British Antarctic Survey for use on larger birds and later miniaturized for use with songbirds. The songbird geo-locators are light (0.05 ounce). The device is essentially a small computer chip with a built-in clock and a short stalk. The geo-locator tracks light levels so that sunrise and sunset are recorded for each day. Knowing sunrise, sunset and day length allows the researchers to precisely determine the position of the bird every day. Essentially, the length of the day allows the latitude to be determined and the time of sunrise and sunset allows the longitude to be determined. Pretty neat!

The geo-locater is held on the rump of the bird with straps that wrap around the upper part of each leg.

The first results of this technique were recently published by a team of researchers led by Bridget Stutchbury from York University. The team captured 20 Purple Martins and 14 Wood Thrushes in the fall of 2007 in northern Pennsylvania. They were able to recapture five of the Wood Thrushes and two of the Purple Martins in the spring of 2008. The researchers downloaded the data from the geo-locater and were able to map the fall migration, winter movements and spring migration of each bird.

Even though only seven birds were recaptured, the results already cause us to rethink how migration occurs in songbirds. In the fall, the two Purple Martins flew south to the Yucatan Peninsula in five days (about 1500 miles in total). The martins stopped there for three to four weeks before continuing their migration to a wintering area to Brazil.

We know that spring migration is typically much faster than fall migration in most birds. There is an urgency about the spring migration as birds stream north to find mates and favorable territories. However, the speed of the Purple Martin spring migration was more rapid than suspected. One of the tagged martins flew from the Amazon basin back to Pennsylvania in only 13 days, traversing over 3000 miles. Four of those days were spent on stopover. Prior to this work, ornithologists believed that a nightly flight of about 100 miles was about the maximum distance most songbirds can manage.

Four of the five Wood Thrushes migrated to the southeastern United States, spending one to two weeks there before flying across the Gulf of Mexico to the Yucatan Peninsula. The birds wintered in Honduras and Nicaragua. Most of the thrushes returned to Pennsylvania in 13 to 15 days, again crossing the Gulf of Mexico. One thrush took the landward route, avoiding the Gulf crossing.

[Originally published on March 21, 2009]

For the Birds - Costa Rica Trip - Part II

This column is the second of two presenting some birding highlights of my visit to Costa Rica in January.

We left the rainforest reserve at La Selva bound for the Ecolodge at San Luis just west of the Continental Divide. The trade winds were unrelenting there, making birding by ear difficult and keeping the birds down.

One of the highlights was a pair of Emerald Toucanets, a mostly green small toucan. A pair of male Black-breasted Wood-Quail were fighting with other, oblivious to the ten people watching them.

In local pastures, I had nice views of Yellow-faced Grassquits, White-eared Ground-sparrows and a Social Flycatcher. Raucous Brown Jays were extremely common.

A local family maintained a bird feeder, stocked with fruit, that attracted Blue-gray Tanagers, Passerini’s Tanagers, Crimson-collared Tanagers (spectacular!), Buff-throated Saltators and Yellow-throated Euphonias. Old friends were seen in the trees: Black-and-White Warbler, Chestnut-sided Warbler and Baltimore Oriole.

We hired a taxi to take us from San Luis to the Monteverde Cloud Forest Reserve for a daylong adventure. This site was only 500 meters higher than San Luis but was truly a different world. Typical weather is misting rain with low-lying clouds. Epiphytes are everywhere on the trees.

The most sought-after bird at Monteverde is the Resplendent Quetzal, a specialist on avocados. We hired three guides to lead our class on a morning walk. The guides knew of an avocado tree where a pair of quetzals were feeding. With patience, we got a good look at a female through a spotting scope. Later in the morning, a male appeared briefly no more than 50 feet way.

The Resplendent Quetzal, a member of the trogon family, is often touted as the most beautiful bird in the world. I find it hard to argue. The male has a brilliant green head, throat and back and a scarlet red breast and belly. The tail is white with four long green uppertail coverts that extend well beyond the tail. The female is similar with more muted colors. Females lack the long tail coverts of the males.

This species is the national bird of Guatemala. Quetzals were revered by the Aztecs, Mayas and other Mesoamerican peoples.
Other avian highlights at Monteverde included a Black Guan, a roosting Mottled Owl, and Ochraceous Wood-Wrens. Several fearless Slate-throated Redstarts flitted about us for a while. These mostly yellow sprites are called candelitos (little candles) by Costa Ricans because their frenetic movements suggest flickering.

We saw seven hummingbird species including the large Green Hermit and Violet Sabrewing. Stripe-tailed Hummingbirds were seen as well. These hummers are nectar robbers. Many flowers with long tubular flowers rely on hummingbirds for pollination. The flowers essentially reward the hummingbirds with nectar for acting as pollinators. Striped-tailed Hummingbirds have relatively short bills. To reach the nectar of tubular flowers, the birds pierce the base of the flower to get the nectar but do not get a shower of pollen on them like other hummingbirds do.

Bananaquits and Common Bush Tanagers were nice finds as well.
Our last stop was the tropical dry forest of Santa Rosa National Park. This park is in the northwest corner of Costa Rica. We were there during the dry season when a strong rain shadow effect of the mountains to the east makes rain a rare event for half of the year. It was very hot during our stay.

Because of the dryness, some of the trees lose their leaves. The forest floor had a significant layer of dead leaves, similar to our northern broad-leaf forests.

The most conspicuous birds were White-breasted Magpie-Jays with their curly feathers on the top of the head. A Roadside Hawk, a buteo hawk, was regularly seen. Three species of parrots were heard and sometimes seen: White-fronted Parrot, Yellow-naped Parrot and Orange-fronted Parakeet.

Hoffman’s Woodpecker was the most common woodpecker. Flycatchers were conspicuous but less diverse than at La Selva. Most were Great-crested Flycatchers, Dusky-capped Flycatchers and Streaked Flycatchers
The resident Rufous-capped Warblers were joined by Yellow Warblers.

The pigeons were represented by three common species: Inca Dove, White-tipped Dove, and White-winged Pigeon.  Thicket Tinamous called from sights unseen. Lots of Ruby-throated Hummingbirds were present. Other neat birds were Barred Antshrikes, Rufous-naped Wrens and Scrub Euphonias. We found a sleeping Northern Potoo, doing a superb imitation of a broken tree limb.
Santa Rosa is a great place to see monkeys. We had several extended views of white-faced capuchin monkeys and howler monkeys.

A trip to the Pacific Ocean (Playa Naranjo) yielded Brown Pelicans, Magnificent Frigatebirds and lots of Brown Boobies. I never got used to the lack of gulls.

[Originally published on March 7, 2009]

For the Birds - Costa Rica Trip - Part I

My colleague Judy Stone and I spent most of January in Costa Rica teaching a Colby biology class. The focus of our course was plants of the tropics but I had time to enjoy some wonderful birding while we were there. I’ll devote this column and the next to some of the birding highlights of our visit.

Costa Rica is a small country, roughly the size of West Virginia. Within that small area, however, the range of climate, topography and vegetation is great. It is no wonder that 875 species of birds occur in Costa Rica. The United States and Canada combined scarcely exceed that number of species.

We spent our first week in Costa Rica at the La Selva Biological Station near the town of Puerto Viejo, north of San Jose. This site, at an elevation, of about 500 feet is lowland rainforest. The trade winds blow across Costa Rica from the east, bringing moisture-laden air off the Caribbean onto shore. As the air rises, it cools and drops the moisture as rain. We were at La Selva during the dry season but, as we learned, La Selva has a rainy season and a rainier season. We were lucky though as most of the rain fell during the evening hours.

The first bird I saw at La Selva looked like a small warbler, flitting near the top of a large tree. It was a warbler indeed but not the tropical species I was expecting. It was a Chestnut-sided Warbler, one of the most common nesting warblers in Maine. I noted a number of other birds that breed here in Maine enjoying the Costa Rican warmth: Turkey Vulture, Tennessee Warbler, Louisiana Waterthrush, Baltimore Oriole and Red-winged Blackbird.

We were assigned rooms in an older building called the River Station, overlooking the Puerto Viejo River. A pair of Crested Guans, chicken-like birds with bright red wattles, were feeding just above the trail on fruits. A Blue-black Grosbeak was in an adjacent tree.








Montezuma’s Oropendolas were the most conspicuous birds at La Selva. These members of the blackbird family are large and loud. Males are about 20 inches long, females five inches shorter. Most black, Montezuma’s Oropendolas have bright yellow tails and conspicuous white markings on the side of the head. Females were just beginning to build their pendant nests in palm trees. The nests are similar to those of a Baltimore Oriole but much longer. Males were displaying to females. The display is memorable. The male perches on a branch and gives a loud, liquid song. At a distance, the song is quite pleasing but metallic screeches can be heard when close to a male. As the male finishes his song, he performs a deep bow, rotating his body a full half turn, showing off his bright yellow tail. Despite the bravura performances, the females seemed unimpressed.

Mornings at La Selva were almost magical. Great Tinamous gave their wavering, flute-like call from deep in the jungle. Rufous Motmots gave their lovely hoot-hoot-hoot calls that reminded me of notes from a wooden percussion instrument. As dawn approached, the glorious songs of White-breasted Wood Wrens, Striped-breasted Wrens and Black-throated Wrens filled the air.

Parrots were vocal but usually difficult to see in the tops of trees. With patience, we got good looks at Mealy Parrots, Red-lored Parrots, Brown-hooded Parrots and White-crowned Parrots. The highlight though was eight fly-over Great Green Macaws. Only about 200 individuals are left in Costa Rica.

Birds at La Selva often move in large, fast-moving mixed flocks. One memorable flock had Palm Tanagers, Passerini’s Tanagers, Dusky-faced Tanagers, Blue-gray Tanagers and Golden-hooded Tanagers. Within five minutes, the flock had moved on.

I enjoyed seeing birds in families that were new to me. A Rufous-tailed Jacamar, related to the woodpeckers, looked alike an overgrown hummingbird with its long thin bill. A pair of Pied Puffbirds provided us with great views; these birds are also related to the woodpeckers. We saw Northern Barred Woodcreepers and Streak-headed Woodcreepers. Woodcreepers are perching birds that behave much like woodpeckers. A Great Antshrike gave me a brief look before diving back into its preferred dense undergrowth habitat.

Other memorable sightings included a male Green Honeycreeper with fluorescent green plumage, Olive-backed Euphonias, a Green Kingfisher and a ton of flycatcher species including Boat-billed Flycatcher, White-ringed Flycatcher, Common Tody-Flycatcher, Mistletoe Tyrannulet, Rufous Mourner, Bright-rumped Attila and Long-tailed Tyrant. Chestnut-colored Woodpeckers, Black-cheeked Woodpeckers and Pale-billed Woodpeckers were striking birds as well.

[Originally published on February 21, 2009]

For the Birds: Maine Christmas Bird Count review

The Maine Christmas Bird Counts conducted from Dec. 14 to Jan. 5 yielded particularly high numbers of sightings of common species, of irruptive species like Bohemian waxwings – and of the rarities whose discovery makes a Christmas Count so exciting.

Perhaps the most remarkable species in this winter's count are the pine siskin and white-winged crossbill. Both are irruptive species, visiting Maine in the winter when their food supplies are depleted to our north.

The pine siskin irruption this year has been nothing short of spectacular. These wanderers have been absent from many Maine Christmas Bird Counts over the past decade. Consider the sightings from this year's counts: 92 in Augusta, 297 in the Belfast area, 361 in Waterville and 350 in Biddeford-Kennebunkport.

Interestingly, pine siskin numbers were quite low on counts dominated by spruce-fir forest that normally have the highest numbers of these sprites. The Misery township (just south of Jackman) and the Schoodic Peninsula counts yielded only four.

The number of pine siskins sighted in Maine has continued to increase over the past month. Peter Vickery of Richmond saw a Eurasian siskin among the pine siskins at his feeder. Get your niger seeds out there for the siskins!

White-winged crossbills have also staged an impressive invasion this winter. Many counts shattered their previous records for this species. The Portland counters found 672 white-winged crossbills – the previous record was eight. Similarly, the Waterville count produced 216, dwarfing the previous high of five.

The Misery count usually produces the most white-winged crossbill sightings, but this year none were found there. I saw lots of white-winged crossbills this summer in coastal Washington County, but none were found in the Moose Island-Jonesport count. The crossbills seemed to have pushed south of their typical winter range.

Common redpolls generally show a biennial pattern of irruption into Maine. Last year, these birds staged a major invasion into the state. One therefore expects this winter to have a light flight of these finches.

Although a number of counts recorded redpolls, numbers were usually low except for the 147 in the Augusta count.

As is typical, Bohemian waxwings had a patchy distribution in Maine over the count period. The Bangor-Bucksport count produced 1,794 Bohemians (and 792 cedar waxwings) and 670 were in the Farmington count. Elsewhere, Bohemians were mostly absent, or present in single digits.

Red-bellied woodpeckers staged a strong invasion into Maine this fall, and a number of them were found by Christmas count participants. The Portland count had 15 red-bellies, eclipsing the former record of four. Six were found in Bangor-Bucksport, eight were found in Augusta and 17 in Biddeford-Kennebunkport.

Blue jays show an intriguing winter movement called partial migration. Some blue jays spend the entire year in Maine, while a proportion will migrate to more southerly areas, particularly if food supplies are low. Blue jays depend heavily on acorns during the winter. The acorn crop must have been more than adequate this year as higher than normal numbers of blue jays were counted in many Maine counts. In Augusta, the 674 blue jays shattered the previous high count of 61.

Maine Christmas Counts usually yield a number of lingering birds that will likely be forced to migrate or perish before the winter is over. Great blue herons are a case in point. Hardy herons showed up on the Biddeford-Kennebunkport, Portland, Thomaston-Rockland, Waterville, Augusta, Moose Island-Jonesport and the Schoodic Peninsula counts.

Other lingering species included a common tern, Eastern bluebirds, hermit thrushes, Carolina wrens, yellow-rumped warblers, a yellow-breasted chat, a summer tanager, Eastern towhees, fox sparrows, a white-crowned sparrow, a grasshopper sparrow and a Baltimore oriole.

Not surprisingly, most of these showed up on counts in the southern part of the state, especially along the coast where the weather is not quite as severe as in northern and inland areas.

As usual, the Portland count recorded the highest number of species in the state. The 114 species tallied represent a new record for the count. Four species were found that had never been recorded on that count: ruddy turnstone, blue-headed vireo, clay-colored sparrow and red crossbill.

As expected, the Misery count yielded the lowest number of species in this challenging environment. Fifteen species were counted, including gray jays, pine grosbeaks and red crossbills.

To see the complete totals for the Maine Christmas Bird Counts, visit www.audubon.org/Bird/cbc

[Originally published on February 7, 2009]

For the Birds: South Carolina trip II

This column is the second of two on the birds seen on a South Carolina coastal visit in late December. This column will focus on a trip to a forest tract near the Santee River north of McClellanville.

Although development pressures along the South Carolina coast continue to increase, significant tracts of land are protected. Much of the biologically rich area along the coastal Santee River is protected by holdings of the Francis Marion National Forest and by Nature Conservancy holdings.

We had the chance to explore a tract of preserved land north of McClellanville on December 31 on a warm sunny day.

We began with 

a walk along a boardwalk through a bald cypress swamp. These conifers have trunks that are swollen at their bases. Each tree puts up a number of knees, short woody growths that extend a few feet above the black water of the swamp. Water tupelos were also common trees, also having buttressed trunks. The surface of the water was a green, unbroken carpet of duckweed, a small aquatic floating plant. You may have seen duckweed in Maine.

The birds here were few, mostly Yellow-rumped Warblers. A small impoundment at the end of the boardwalk had no ducks. We did see a large number of Double-crested Cormorants and a lone Anhinga flying toward an adjacent impoundment.  We backtracked down the boardwalk and walked toward the second impoundment. On the way, a Red-shouldered Hawk called repeatedly overhead.

At the second impoundment, we found a number of cormorants. I was glad I had lugged my spotting scope along because we enjoyed leisurely views of two Belted Kingfishers perched on the bank in perfect light.

Lots of Hooded Mergansers were on the water along with a Pied-billed Grebe. A Great Blue Heron and a Great Egret were patrolling the shallows for incautious fish. Hundreds of Tree Swallows were hawking unseen insects above the water.

Walking around the impoundment along a woodland path, we heard the chip notes of Yellow-rumped Warblers and Ruby-crowned Kinglets in the upper reaches of the live oaks. I began to pish to try to draw the birds closer. (In case you have never heard a birder pish, the birder rapidly repeats “psssh” to mimic a general alarm call. Landbirds will often come close to investigate and possibly mob the intruder.)

Before long, 60 birds were close by. Ruby-crowned Kinglets were the most common although we picked out a Golden-crowned Kinglet, several titmice, a White-breasted Nuthatch and Carolina Chickadees. At least one Pine Warbler was among the many yellow-rumps. Quite a spectacle.

Continuing along the path, we came to a sluice that controls the level of the water in the impoundment. Forty feet away, two Wood Storks were perched on a tree adjacent to the outflow stream. They sat calmly while we enjoyed watching them through the spotting scope.

A Brown Pelican was on the water in the impoundment. Brown Pelicans generally occur in saltwater habitats but occasionally venture into freshwater habitats. A Pied-billed Grebe could be in the same scope view as the pelican.

It is hard to go for very long in coastal South Carolina without seeing vultures. A number of Turkey Vultures hovered during most of our walk. Black Vultures were present as well although in lower numbers. Telling the two species apart is flight is straightforward. Turkey Vultures hold their wings in a shallow V while soaring while Black Vultures have their wings extended horizontally like an eagle or Red-tailed Hawk. The tail of a Turkey Vulture is long while that of Black Vultures is noticeably short. When a Black Vulture spreads its tail, the tail seems to disappear into the hind margin of the long wings. Finally, Black Vultures have a large white area on the tip of the underwing. Seen in the right light, these white areas glisten against the black background.

We were pleased to see some butterflies on the wing. A Cloudless Sulphur, a larger relative of the Clouded Sulphur that is so common in Maine, flitted by. We saw several Red Admirals, perched on the ground. The butterflies were courting mates and occasionally flew up for a brief dogfight with another admiral. Red Admirals feed on sap and decaying matter so the rarity of flowers posed no problem for them. We saw a few Green Darners, a large dragonfly with a striking green head and blue body.

On the way back to the parking lot, we walked through an open field with scattered trees. This area looked like perfect habitat for Eastern Bluebirds and so it was. At least six were present. Extended views through the spotting scope of two males perched on the outer branches of a live oak provided a fitting end to a wonderful trip.

[Originally published on January 24, 2008]

For the Birds: South Carolina trip I

My wife and I took a holiday trip to North and South Carolina in late December. We spent five delightful days on the South Carolina coast with friends in McClellanville, South Carolina. The birding and the weather were delightful.

The maritime forest of the Carolinas is dominated by live oaks. These evergreen oaks rarely exceed fifty feet in height but have many large horizontal branches that extend out for tens of feet and then grow upward to the canopy. Foresters report that some live oaks can occupy a full acre! The trunks of these trees are large with diameters regularly exceeding six feet. The largest live oak known had a diameter of 11.5 feet.

The small fishing town of McClellanville is dominated by live oaks. The few roads through the village seem to be tunnels through these great trees.
The live oaks provide habitat for many birds. Walks through the village turned up Carolina Chickadees, Tufted Titmice, Carolina Wrens and tons of woodpeckers, the most common being Northern Flickers, Red-bellied Woodpeckers and Downy Woodpeckers.

Yellow-rumped Warblers are common wintering birds in this part of the world. Most warblers rely on insects gleaned from leaves for their food year-round. Most of the warblers that nest in North America are now on Caribbean islands or in Central and South America. The Yellow-rumped Warblers are more flexible in their diet and switch to fruit eating during the winter. These warblers depend on the fruits of the abundant wax myrtle bushes found along the coast of the southeastern United States. Of course, they will feed on insects if they can find them. But their ability to switch to fruit eating means they do not have to make the arduous migration to tropical climates to pass the winter.

My ears told me I was not in Maine when I walked out of the house on morning to hear the energetic fee-bee of an Eastern Phoebe. Like the Yellow-rumped Warblers, the phoebes will switch to small fruits when the flying insects they depend on are not easy to find.
An unusual sound in the village was the three-note song of a recent colonist, the European Collared Dove. The song is a set of three coos, with the second one longer and stronger. It has the same cadence as the word “united”.

The European Collared Doves are native to southeastern Europe. These birds were introduced in the Bahamas in 1970 and spread to Florida by 1982. The species has expanded in the United States reaching Veracruz, Mexico, the Great Lake states and even British Columbia. I know of a single record from Maine on Monhegan Island. The largest densities of these birds are in the Gulf coast states.

Some ornithologists think the Collared Doves are taking the place of the extinct Passenger Pigeon that was so abundant in the United States until the latter part of the 1800’s.
It’s too early to tell what effect if any the Collared Doves are having on our native birds. The expansion of their population seems slower than the explosive invasion of the birds into western Europe fifty years ago.

Our friends in McClellanville have s small skiff so we were delighted to take a bird excursion through the maze of streams that divide the huge salt marshes of the area. Buffleheads, Hooded Mergansers and Red-breasted Mergansers were the most common ducks. Occasionally, a Bottle-nosed Dolphin would break the surface of the water near the boat. Boat-tailed Grackles were common in the salt marsh.

Two Bald Eagles were a real treat. A Red-tailed Hawk perched atop a navigation pole and a Merlin streaked by at breakneck speed.

Brown Pelicans were common. I still marvel at the ability of these birds to glide effortlessly just above the water. We also saw a flock of 40 White Pelicans, regular wintering boards along this portion of the coast. Unlike the Brown Pelicans that dive to capture fish, White Pelicans are social hunters. A group of White Pelicans will form a semicircle just offshore and swim toward the shore, driving any small fish into the center of the semicircle where they can be captured by simply bobbing underwater. White Pelicans do not dive.

The exposed intertidal flats had a nice mixture of shorebirds. Sanderlings, Dunlin, Short-billed Dowitchers and Piping Plovers were seen. It was hard to miss the American Oystercatchers with their raucous calls and their striking appearance (black and white plumage and long red bills).

Double-crested Cormorants, Common Loons, a single Red-throated Loon, Northern Gannets and Belted Kingfishers made it to our list as well.

In the next column, I’ll describe a wonderful trip to the coastal forest of the Santee River.

[Originally published on January 10, 2009]

For the Birds: American Crows

Have you been seeing large numbers of American Crows converging from all directions shortly before dusk? Shoppers in Waterville and Augusta are often surprised as nocturnal roosts of crows start to build close to shopping malls. The roost in Waterville must number in the thousands of crows.

It often takes a spectacular aggregation of crows for us to even notice them. American Crows are common, seen every day by anyone with an eye for nature. We take crows for granted. Yet, these birds have some fascinating behaviors and traits that reward a careful look.

Let’s start with their roosting behavior. Night-time roosts may contain fewer than 100 birds to tens or hundreds of thousands. One well-known roost in Oklahoma contains around two million crows!

The reasons for roosting are unclear. A large flock of birds is certainly more vigilant against predators. A large bird of prey has little chance of sneaking up on a roost of crows.

A controversial explanation for roosting in birds is to provide a way to exchange information about food locations. However, no one has convincingly shown that crows exchange information at their roosts.

Roosts often occur, like the ones in Waterville and Augusta, in urban areas. We know that the minimum temperatures in the vicinity of human developments (houses, roads, parking lots) can be as much as ten degrees warmer than in undeveloped areas. On a cold Maine night, every degree of warmth can help birds make it through the night.

In the morning, crows leave their roosts but usually do not leave alone. Crows have a stable family structure. Groups of birds consisting of a mated pair (crows mate for life) as well as their offspring from several different years leave together. This group defends a territory against other flocks of crows.

American Crows are widely distributed in North America. They are found throughout the United States except for portions of southeastern California, western Arizona, and most of Utah and Nevada. American Crows are found broadly across the southern half of Canada.

American Crows occur in a variety of habitats but are most common in open woodland areas. With the clearing of eastern forests by European colonists, American Crows increased in abundance after European colonization. Regarded as agricultural pests, American Crows were persecuted for most of the 19th century and the early part of the 20th century. The crows found that towns and cities provided a refuge from hunters and began to use urban and suburban habitats. With their broad diet, American Crows have little trouble finding food to eat in urban and suburban environments.

Like most members of the family Corvidae (jays, crows and ravens), American Crows have a broad diet. One can aptly describe them as omnivorous because their diet includes terrestrial and marine invertebrates, amphibians, reptiles, small birds and mammals, the eggs, nestlings and fledglings of birds, seed crops of various types, fruit, carrion and the French fries and other food that humans discard.

Over 200 species of birds share the behavior of cooperative breeding. Offspring from an earlier brood or grandparents, aunts, uncles or cousins may assist a breeding pair in raising their young. Many of the best studied species that display cooperative breeding have exotic names to North American birders: Superb Starling, Superb Fairy-wren and Gray-crowned Babbler, to name a few. Yet, we have a cooperative breeder right in our midst. American Crows show this intriguing nesting behavior.

The nature of cooperative breeding varies across North America. In Massachusetts, 94% of American Crow pairs had helpers with an average of 4.2 birds helping raise a clutch of eggs. In Florida, the cooperating group was even larger with 7.2 birds on average helping to raise the young.

Young birds may help their parents for up to six years before they become parents for the first time. Helpers make themselves useful in a number of ways. Helpers may help with nest building, help keep the nest clean, feed the incubating female and the nestlings and guard the eggs and nestlings when the parents are away from the nest.

The vast majority of helpers are related to the young that they help raise to fledging. The helpers therefore share genes with the current brood. So by helping to raise brothers or sisters, they are perpetuating some of the own genes without reproducing themselves.

We are use to hearing the caw of American Crows but their vocal repertoire is actually quite large. Many variants of the caw exist and they can also produce other sounds including screeches, barks, rattles, grating sounds and clicks. Carefully study of the variety of crow vocalizations is amazing.

[Originally published on December 27. 2008]

For the Birds: Waxwings

With their silky sleek plumage, bold black eye stripes, black chins and prominent crests, waxwings are one of our most handsome birds. We have two species of waxwings in Maine, the Cedar Waxwing and the Bohemian Waxwing. Both species can be currently found in Maine.

There are just three species of waxwings in the world. The Cedar Waxwing is restricted to North America. The Bohemian Waxwing is found broadly across the boreal habitat of the northern hemisphere. Bohemians occur in North American and across the breadth of northern Eurasia. The third species, the Japanese Waxwing, This species nests in southeastern Russia and adjacent China and winters mainly in eastern China, Korea and Japan.

Waxwings are so named because of the bright red, teardrops of waxy material found on some of the wing feathers and to a lesser extent on the tail feathers. The function of these wax drops is not known.

The Cedar Waxwing is a common and widespread breeding bird in Maine. During the summer, they flit from tree to tree, giving their characteristic, buzzy zirr-r-r calls. During the summer, Cedar Waxwings eat flower petals, sap and insects as well as small fruits. During the winter, fruits make up most of the diet. The fruits of mountain ash are high on their list of preferred fruits in the winter although rose hips, juniper berries, hawthorn fruits and many ornamental berries are taken as well.

Cedar Waxwings are often hard to find in Maine in the winter. Most of our breeding Cedar Waxwings migrate to more southern states for the winter, often flocking in groups of hundreds of birds. A nice flock is gracing us with their present on the Colby campus now but will likely move south before the winter is over.

The Bohemian Waxwing is an erratic winter visitor to Maine. Befitting their name, these birds are known for their nomadic wandering in the winter in search of fruit. Bohemian Waxwings nest in western North America, mostly in Canada and Alaska. When fruit crops in western North America are poor, these birds move east searching for dependable food supplies. In some years, Bohemian Waxwings are absent; in other years, they may be abundant. Huge flocks may locate a good food supply and then depart as soon as all the fruit is eaten.

Flocks of Bohemian Waxwings are generally much larger than flocks of Cedar Waxwings. More than 3000 birds have been found in one Bohemian flock; Cedar Waxwings usually occur in flocks of fewer than 100 birds.

“Drunk drivers” can be found in groups of waxwings. Sometimes, waxwings will feed on fermented fruit. The alcohol contained in the fermented fruit intoxicates the waxwings, which then have difficulty flying and even standing when they overindulge.

The gut of waxwings is well adapted for fruit eating. The bill and esophagus are both broad enough to allow fruits to swallowed whole. Fruit eating poses a physiological demand on waxwings. Winter fruit tends to be high in sugars but low in water and nutrient content. The passage of this food through the gut upsets the water balance of the bird, forcing the bird to drink often.

The low nutritive value of waxwings’ food means these birds must eat a lot of fruit to meet their daily dietary needs. The result is a rapid passage of material through the birds. The next time you encounter a flock of feeding waxwings, listen for the near constant rain of bird droppings falling on the ground.

How can you tell the two species of waxwings apart? Bohemian Waxwings are slightly larger and grayer than Cedar Waxwings. Sometimes, both species occur in the same flocks so a direct comparison is possible. However, there are better ways to distinguish the two species.

The Cedar Waxwing has wings without the yellow spots that are found in Bohemian Waxwing wings. The belly of Cedar is yellowish while that of Bohemian is grayish. However, the best mark is to look at the color of the undertail coverts. These are the short feathers at the base of the underside of the tail. In the Cedar Waxwing, these feathers are white. In the Bohemian Waxwing, they are a bright cinnamon color. It is easy to pick out this difference at a great distance, making the color of the undertail coverts the most useful identification feature.

Waxwings are often described as birds of the woods but that claim is a bit misleading. Waxwings are generally found in open woodlands, on the edges of tracts of forest or in regenerating forests where their favored fruits are abundant.

[Originally published on December 13, 2008]

For the Birds: Bird Feeding Effects - Part II

Gillian Robb, an Irish ornithologist, and several of her colleagues have recently published a review of avian responses to supplemental feeding in the journal Frontiers in Ecology and the Environment. I discussed some of their points in the last column and will continue that discussion in today’s column.

Providing supplemental food to breeding females may allow them to spend less time looking for food and more time incubating the eggs or dependent young. Such an effect has been clearly shown in a study of Australian reed warblers and is likely a general phenomenon.

Given extra food, parents can either spend less time foraging for food to give their nestlings or use their extra time to find even more natural food for their young. In most species studied, parents simply spend less time looking for food rather than ambitiously trying to give their young even more food.

Chicks given supplemental food were much more likely to fledge than chicks without access to extra food in nearly two-thirds of the studies Robb reviewed. Black-legged Kittiwakes show one of the most striking effects. Adults fed supplemental food over two years, fed in turn to their chicks, fledged twice as many chicks in their first year and three times as many in the second year as kittiwakes that were not given extra food.

Given the difficulty of finding food for many birds, it is not surprising that supplemental feeding can alter the behavior of birds. Varied Tits (a chickadee relative) reduced their participation in winter mixed-species flocks when given extra food. Mixed-species flocks form when food is scarce and patchy.

The authors cite some of my research on Black-capped Chickadees in the North Woods of Maine. By providing supplemental food, I found that winter territorial boundaries break down. As many as 10 different winter flocks used the same feeders over the course of a single day.

Supplementary feeding may affect bird reproductive behavior. When House Sparrows were provided with extra food, the males stayed closer to their nests. Females cheating on their mates by mating with other males decreased because of the increased presence of the male.

Providing food to birds can alter the distribution of birds over large geographic areas. The northward expansion of Northern Cardinals may have resulted, at least in part, from backyard bird feeding. In Finland, ornithologists strongly suggest that backyard feeding explains a tendency of birds to overwinter in Finland rather than migrate south.

A contentious topic related to bird feeding concerns the degree to which birds become dependent on our handouts. In Finland, Great Tits feed most of the time from feeders and ornithologists suggest that these birds are so dependent on supplemental food that they could not survive without the freebies. So, feeding stations can be seen as ecological traps.

However, a study in Wisconsin with Black-capped Chickadees failed to find such feeder dependency. A population of chickadees that had been fed for 25 years was deprived of extra food in one winter. Those birds survived at the same rate as other chickadee populations close by that had never been given supplemental food.

Winter feeding can increase the density of resident birds in an area. These birds may stay in the area to nest during the summer, inflating the number of breeding birds. Jays and crows living close to humans take up to 75% of their food from human handouts. The local increase in these birds poses a threat to other songbirds because jays and crows are efficient egg predators.

Bird feeding can have indirect impacts as well. The gathering of large numbers of birds at one place increases the likelihood of the spread of diseases. The bacteria Mycoplasma and Salmonella are particular threats. The increased risk of disease at bird feeders in the United Kingdom is so high that the Garden Bird Health Initiative was begun, which prescribes bird feeding practices to lower the risk.

Some people that feed the birds are concerned that the high concentration of birds attracts birds of prey like Sharp-shinned Hawks or Cooper’s Hawks. Happily, research has shown that birds frequenting feeders are not more likely to be killed by predators. Large groups of birds are vigilant; the approach of a predatory bird or mammal is usually detected by the many watchful birds at a feeder.

We still have much to learn about the effects of bird feeding. Most studies have been conducted at a single feeder rather than at widely dispersed feeders, reflecting the distribution of households that feed the birds.

Should we feed the birds? To date, we believe the benefits exceed the risks. So, keep those feeders filled!


[Originally published on November 28, 2008]

For the Birds: Bird Feeding Effects - Part I

Feeding the birds is an activity that has increased greatly in the past 40 years. In the United States, 43% of households maintain bird feeders. In the United Kingdom, bird feeding is even more popular; 75% of households there feed the birds.

Homeowners in the United States and the United Kingdom purchase 500,000 tons of birdseed each year. This bounty is enough to support 300 million chickadees living on nothing else. In short, bird feeding represents a major subsidy to many species of birds.

We know that food often limits bird populations so bird feeding may have positive benefits for birds. However, we know surprisingly little about the effects of bird feeding, particularly on larger geographic scales. Most of the work that has been done, including some of my own, has been concerned with local effects.

Gillian Robb, an Irish ornithologist, and several of her colleagues have recently published a review of avian responses to supplemental feeding in the journal Frontiers in Ecology and the Environment. Today’s column is the first of two in which I will summarize the major points of the article.

The energetic costs of reproduction are huge for birds. Favorable times for nesting are often brief in birds so an early start may be beneficial for breeding birds. In 34 of 59 studies reviewed by Robb, bird feeding resulted in earlier nesting. In most cases the shift was less than a week but in some a shift was as long as a month earlier.

Unfortunately, earlier nesting can sometimes result in negative impacts. Birds given supplemental food may begin nesting before their natural food supply becomes abundant enough to provide enough nutrition for their nestlings. As an example, chickadee adults do well feeding on sunflower seeds but their nestlings need caterpillars and other sources of animal protein to allow the nestlings to grow and thrive.

Food supplementation can affect the quantity and quality of eggs laid by female birds. In 44 studies reviewed by Robb, 28 presented evidence that bird feeding increased the number of eggs laid.

As an alternative (or as a second effect), a female bird with access to supplemental food may increase the quality of her eggs by laying larger eggs. Larger eggs cool more slowly than smaller eggs when the adults are off the nest; larger eggs have a greater chance of hatching than smaller eggs.

Florida Scrub Jays given high-fat, high-protein food laid eggs with more water and protein in them. Some popular bird foods may be a rich source of macronutrients. For instance, peanuts are high in vitamin E. This vitamin E can be passed into the eggs by a female bird. These enhanced nutrient levels result in better immune responses by nestlings to the threats of disease.

Supplemental food may increase the chances that a pair of birds can have two clutches during a single breeding season. For instance, when Black-throated Blue Warbler females were given food after their first clutch, all of the females started a second clutch compared to only 50% of the females that were not given supplemental food. This effect even carried on into the next year. Two-thirds of the females given extra food in one year had two broods the following year compared to none for the females not given extra food in the prior year. This striking result shows the dramatic and long-lasting effect that bird feeding can have on bird reproductive success.

In humans, the sex of a baby is determined by the sex chromosomes. Females have two X chromosomes whereas males have a single X chromosome and a much smaller Y chromosome. In birds, sex is determined in the opposite way: males have two similar chromosomes (called Z chromosomes) while females have a Z chromosome and a smaller W chromosome.

Birds differ from mammals in that female birds have the ability to control the sex ratio of their young. The kakapo, a flightless parrot found only in New Zealand, provides an interesting example. The kakapo is an endangered species whose population declined to as few as 70 individuals.

Wildlife biologists decided to try to increase the nesting success by giving the female kakapos supplementary food. Unfortunately, the kakapo females that received the extra nutrition responded by producing more male offspring! So the wildlife biologists had to lower the amount of extra food provided to strike a happy medium: enough to increase the nesting success of the female but not so high as to cause the females to produce mostly male offspring.

Stay tuned until the next column for more information on the impacts of feeding the birds.

[Originally published on November 14, 2008]

For the Birds: Recent Ornithological Research

In today’s column, I will recap some of the articles that have been published in major North American ornithology journals this year. The emphasis will be on birds that occur in Maine.

All of us are thrilled when Evening Grosbeaks come to visit at our bird feeders. For readers who have been birding for at least 20 years, you will no doubt remember times when Evening Grosbeaks descended in large flocks, quickly devastating the sunflower seeds in your feeder. Sadly, these large flocks seem a distant memory.

In a recent article in the Condor, David Bonter and Michael Harvey of the Cornell of Laboratory of Ornithology used 18 years of Project FeederWatch data to quantify the changes in Evening Grosbeak abundance. Their analysis confirms our impressions: Evening Grosbeaks seem to be in a population decline. Over the past 18 years, the number of sites reporting Evening Grosbeaks fell by 50%. Flock sizes decreased by 27% at feeders where the grosbeaks still visited.

The authors do not know why the population is decreasing but argue that the reason for these declines needs urgent investigation.

The Boreal Chickadee has a more northerly distribution than the Black-capped Chickadee. Boreal Chickadees also prefer coniferous forest. In Maine, these chickadees occur in the mountains, in the spruce-fir forest of northern Maine and in the spruce-fir coastal forests from Mount Desert Island eastward.

Adam Hadley and Andre Desrochers of Universite Laval recently described the effects of logging practices on Boreal Chickadee habitat use in Quebec. They clearly showed that Boreal Chickadees prefer the taller (greater than 7 meters in height), commercially valuable stands of conifers (mostly balsam fir in their study area) during the winter. The birds typically move in stable flocks of four birds. The average flock territory is around 50 acres. Boreal Chickadees occurred less often in regenerating forest where the trees were between four and seven meters tall. The chickadees avoided clear-cut areas and younger stands with trees less than 4 m in height.

The authors expect that forestry practices in Quebec will result in substantial loss of prime Boreal Chickadee winter habitat over the next 20-30 years. Boreal Chickadees will likely show apparent habitat declines although the population may remain stable. The reason is that the winter flocks will need to expand their territory size in less preferred areas and therefore will be harder to detect.

On the positive side, Wild Turkey populations have risen rapidly over the past 20 years. In the early 1990’s, the sighting of a Wild Turkey was an unusual event in Maine. Seeing flocks of Wild Turkeys now is commonplace and many of us have them digging through our flower beds and vegetable gardens.

During the breeding season, male turkeys display and gobble to attract female mates. The toms have no parental role and therefore a tom seeks to have as many female partners as he can attract. We think that female turkeys may have multiple male partners as well so eggs from a single clutch may be fathered by multiple males.

Alan Krakauer of the University of California has made a fine contribution to our understanding of turkey mating systems in an article published in the Condor. His work was done in central California; one expects that similar results would be seen in eastern turkeys.

Krakauer used DNA fingerprinting techniques to examine the paternity and maternity of nestling turkeys. The DNA results do not lie. Krakauer took DNA samples from all the eggs of 32 nests. He showed that Wild Turkeys at his study site did not have as many partners as one might expect. Nestlings in 15 of the nests had the same mother and father. The broods from 14 nests were often half-brothers; they had the same mother but a different father. In seven nests, the embryo DNA showed that the eggs were produced by more than one female. Clearly, a sneaky female dumped one or more of her eggs into the nest of an unsuspecting female.

In songbirds, the female usually incubates the eggs. She develops a brood patch, an unfeathered area with an extensive blood supply to allow the female to transfer heat to her eggs. Margaret Voss and colleagues from Penn State described male incubation in Barn Swallows. Unlike female Barn Swallows, the males do not develop a brood patch. As a result, they are much less efficient in keeping the eggs warm than the female. Nevertheless, male incubation is better than having no incubation at all so male incubation gives the females the chance to feed for a longer period of time when she takes a break from her incubating duties.

[Originally published on October 31, 2008]

For the Birds: Review of Roger Tory Peterson Biography

All students of nature are familiar with the name Roger Tory Peterson. Peterson is given much credit for the rise of field birding in this country and abroad. In 1934, he published his Field Guide to Eastern Birds. This book was a vast improvement over earlier identification guides to birds that were too bulky for field use, sparsely illustrated or incomplete in their coverage. Peterson’s guide was meant to be taken in the field. In later years, Peterson was always delighted to be asked to sign battered, well-used copies of his guide because that meant the field guide was used as he intended.

Peterson was innovative in painting birds from the same perspective, usually a lateral view looking to the right. The male was typically shown in front with the female partially overlapping behind the male. Perhaps his most useful innovation was the use of arrows to point to characteristics that are most useful in identifying species. His text descriptions were to the point and easy to understand. For instance, to identify the Snowy Egret he told the birder to look for the golden slippers.

Over the years, Peterson revised his eastern bird guide three times and a fifth edition was completed posthumously by colleagues. He also produced bird guides for western North America, Mexico, Europe as well as a wildflower guide. He painted the illustrations for all of these guides. For this 1980 revision of his eastern bird guide, he painted very bird anew. His publisher, Houghton-Mifflin, used these books a starting point for the Peterson Field Guide series. Specialists in other groups of organisms prepared field guides using the Peterson arrow system. I am sure you have seen these guides on such diverse groups as ferns, trees, reptiles and amphibians, butterflies, and mammals.

Peterson’s contributions to birds went far beyond the field guides. In his nearly 88 years of life, Peterson was an educator, photographer and conservationists as well as a popularizer of birds. His accomplishments can be appreciated by reading the newly published first biography of Peterson written by Elizabeth Rosenthal. The book is titled “Birdwatcher: The Life of Roger Tory Peterson” and it is a gem.

Rosenthal dug deeply in her exploration of this rather complicated man. She interviewed well over 100 people including this two sons from his second marriage, borrowed letters from a number of Peterson’s correspondents, scoured the archives of the Roger Tory Peterson Institute in Peterson’s hometown of Jamestown, New York and mined the literature for information on Peterson.

Rosenthal chronicles formative events in Peterson’s childhood and early adulthood, including his joining the Bronx Bird Club, a loosely organized group of boys and young men with keen interests in birds. Peterson had moved to New York City to take some design courses to hone his artistic skills and discovered this club. Several of the club members went on to distinguished careers in ornithology and wildlife biology.

Through a series of events, Peterson taught at the Chewonki School in Wiscasset, Maine where he began the strong interest in nature study there at persists to this day. Peterson also regularly participated as a leader at the fledgling National Audubon Society camp on Hog Island in Maine during summers in the mid 1930’s.

Rather than providing a strictly chronological account of Peterson’s life, Rosenthal covers his adult with a number of thematic chapters. Chapters overlap broadly. I think of each chapter as a layer of Peterson’s life. By the end of the book, the reader has a good understanding of the man’s accomplishments, ambitions and personality.

I knew about Peterson’s cross-country trip with the British ornithologist, James Fisher in 1953, chronicled in the book “Wild America”. I did not know that a tour guide, Gus Yaki, recreated the trip 30 years later and that Peterson joined portions of that tour. That is the mark of an influential person.

We learn that Peterson was not a confrontational man but held strong views about the importance of bird conservation. We learn of his efforts to protect the million flamingos that use Lake Nakuru in Kenya, the diverse Coto Donana region in Spain and early efforts to sound the alarm about the negative impacts of DDT on birds and other animals. He played a major role in the development of the World Wildlife Fund.

We discover that Peterson had his share of human foibles. He was a poor driver and a forgetful person. His concentration on his painting and his travels once he became a celebrity came at the cost of his family life.

By the end of his life, Peterson had been awarded 21 honorary doctorates and the Presidential Medal of Freedom. By reading Rosenthal’s biography, you will understand why.

[Originally published on October 18, 2008]

For the Birds: Fox Sparrow; Citizen Ornithology Science Opportunities

In the grand spectacle of the fall bird migration, the arrival of October signals the end of the migration of most warblers and other insect-eating birds. For songbirds, I think of October as the month of the sparrows. Relying on the seeds of grasses and other plants, sparrows can find sufficient food through the fall. There are slim pickings of caterpillars for warblers and other insect-eating birds now.

I keep a sharp eye on the ground these days, particularly below our bird feeders. I’m looking for a noticeably larger sparrow than the Song Sparrows that are so common now. The sparrow I am seeking is the Fox Sparrow, one of the largest sparrows in North America.

Our Fox Sparrows share with the Song Sparrow a strongly streaked breast. As befits their name, Fox Sparrows in the east have a strong reddish cast to their upperparts and head. These are handsome birds.

Although Fox Sparrows nest sparsely in the northwestern part of our state, most of the Fox Sparrows we see are passage migrants. That is to say, the birds nest to the north of us and winter to the south. We see them coming and going during their spring and fall migrations.

Fox Sparrows nest in a large swath across the northern portion of North America from Labrador in the east, across the Canadian provinces into most of Alaska. Breeeding populations are also found at altitude in the Rocky Mountains into Colorado and in the Sierra Nevada down to central California. The wintering ground is essentially the southeastern quadrant of North America with some wintering in the lowlands of California.

Audubon saw Fox Sparrows in Labrador in 1834. The Fox Sparrows in Labrador have the rufous feathering of the birds that pass through Maine. Audubon had no idea how variable Fox Sparrows are across their breeding range.

This striking geographical variation has resulted in the description of 18 distinct subspecies grouped into three or four larger groups. An ornithologist at the University of Minnesota, Robert Zink, has analyzed the DNA of Fox Sparrows from many of these groups. His results suggest that there may be as many as four species all currently called Fox Sparrows. Common names have been given to these distinctive forms: the Reddish Fox Sparrow of eastern North America, the Sooty Fox Sparrow that nests from the Aleutian Islands of Alaska south to Washington state, the Slate-colored Fox Sparrow that nest in the Rockies and the Thick-billed Fox Sparrow nesting from Oregon south to southern California.

I find Zink’s recommendation that Fox Sparrows be split into several species compelling. However, the American Ornithologists Union Check-list Committee, the body that approves all taxonomic changes of Western Hemisphere birds, is not fully convinced and so far Fox Sparrow is considered to be a single, highly variable species. Stay tuned; I expect Fox Sparrow will be split into several species in the not too distant future.

The different types of Fox Sparrows show markedly different migratory strategies. The Reddish Fox Sparrows have a long migration from northern Canada breeding grounds to wintering grounds as far south as the panhandle of Florida. Californian Thick-billed Fox Sparrows migrate only short distances, sometimes just descending the mountain that they nest on to spend the winter.

Despite the broad geographic reach of these sparrows, significant gaps in our knowledge of their nesting biology exist. On the breeding grounds, Fox Sparrows are somewhat shy. Furthermore, they tend to nest in short, dense shrubs making nest-finding and observations of parents at the nest extraordinarily difficult. Add to these factors the fact that Fox Sparrows tend to nest where human density is low.

Winter Bird Counts

It’s not too early to think about the joys of winter birding. Any Maine birder has two opportunities to participate in an organized winter bird count. The first is the National Audubon Society Christmas Bird Count, which will occur from December 14 until January 4. A list of the dates for many Maine counts can be found at: http://www.mainebirding.net/events/cbc

Birders of all skill levels are welcome. Find a count on the list above close to you and give the compiler a call or email to join up. We now have over 100 years of data on the abundance of birds in the early part of winter.

A second opportunity is The Great Backyard Bird Count, organized by the Cornell Laboratory of Ornithology and the National Audubon Society. This count will be held in the deep of winter on February 13-16, 2008. Participants count the birds at their feeders and report their counts online. To sign up for this valuable citizen-science project, visit http://www.birdsource.org/gbbc/


[Originally published on October 4, 2008]

For the Birds: Spencer Baird and the Army Surgeons

Careful study of shorebird flocks at this time of year can yield sightings of peeps that are a bit larger than the Least Sandpipers and Semipalmated Sandpipers that are so common this time of year. This larger sandpiper has wings that extend beyond the tail and tends to feed in the upper portion of the intertidal zone or lake edge. This species is the Baird’s Sandpiper. This species has been seen this fall in Fryeburg, Appledore Island, Cape Elizabeth, Scarborough, Reid State Park, Machias and Lubec.

Today’s column is not about this sandpiper but rather it’s namesake. Spencer Fullerton Baird was one of the great scientists of the 19th century. He made great contributions to ornithology and ichthyology. A prolific author, he also wrote papers on geology, botany, anthropology and general zoology.

Baird’s accomplishments are commemorated not only in the name of Baird’s Sandpiper but Baird’s Sparrow of the western U.S., Baird’s Trogon from Costa Rica and Panama, Baird’s Beaked Whale, a number of fish species and even a species of crab.

Baird was born in 1823 in Reading, Pennsylvania and graduated from Dickinson College in Carlisle, Pennsylvania in 1840. Baird became interested in birds in his mid-teens and began to assemble his own bird collection. He visited the Philadelphia Academy of Natural Sciences in 1839 to read the works of John James Audubon. Baird gathered the courage to write to Audubon in 1840 about a flycatcher that Baird thought might be a new species. Audubon responded in short order and the two became friends.

After graduating from Dickinson College, Baird began medical studies in New York City. Medical studies failed to captivate him and he discontinued his medical education after three months. Baird returned to Dickinson College where he accepted a position as professor of natural history. Baird was an extremely popular professor, leading students on long field trips and maintaining the natural history museum.

In 1847, Baird learned that the Smithsonian Institution was opening. He wrote to Joseph Henry, the first secretary of the Smithsonian, asking for a position as a curator. Baird heard nothing for a while but Henry eventually decided the Smithsonian should have a museum. He offered Baird the job of organizing the museum. Baird eagerly accepted in 1850. He shipped his collection to the Smithsonian, a collection that filled two railroad boxcars! This collection included over 500 species of birds. This generous donation became the core of what is now the United States National Museum of Natural History.

Baird served as the assistant-secretary of the Smithsonian from 1850 until 1878. He became secretary in 1878 when Joseph Henry died.

At the Smithsonian, Baird developed a large network of collectors and natural historians in this country and abroad. Their numbers were in the hundreds. He prepared detailed instructions for the collection and preparation of various kinds of organisms. These instructions were distributed to his network of collectors. He offered encouragement, advice, supplies and money in exchange for the steady stream of specimens arriving regularly in the museum. Baird described many of the new species the collectors found in honor of the collector.

During Baird’s tenure at the Smithsonian, westward exploration was capturing the imagination of many Americans. From 1850 to 1880, the U. S. government initiated a number of expeditions to map the regions and find suitable areas for roads and railroads. Many of these expeditions were conducted by the U. S. Army.

Baird realized a good opportunity when he saw it and recruited physicians with interests in natural history, especially ornithology and mammalogy, to accompany these army expeditions. These physicians collected specimens in their free time, often with the assistance of enlisted soldiers and even sometimes their commanding officers.

These physician/naturalists will be familiar because their names are memorialized in the names of western birds. Elliot Coues was probably the most influential of all of these surgeon/naturalists. The Greater Pewee was formerly called Coues’ Flycatcher. Born in New Hampshire, Coues published his first ornithological paper before his 20th birthday. He spent time in New Mexico and Arizona. Grace’s Warbler in Arizona was first collected by Coues in Arizona. The species was formally described by Baird and named in honor of Coues’s sister, Grace. Baird also named Virginia’s Warbler after the wife of another physician/naturalist, William Anderson.

Other surgeon/naturalists in Baird’s network were John Xantus (Xanthus’s Murrelet), Charles Bendire (Bendire’s Thrasher), William Hammond (Hammond’s Flycatcher) and Adolphus Heermann (Heermann’s Gull).

Baird retired from the Smithsonian to Woods Hole, Massachusetts. He played a major role in the creation of the Marine Biological Lab there, one of the most respected marine laboratories in the world.

[Originally published on September 20, 2008]

For the Birds: Arctic Tern Migration; The Life of the Skies Review

The fall bird migration is picking up momentum. Swallows began massing in large flocks and heading southward by the middle of August. Shorebirds that nest on the arctic tundra are building in numbers along Maine mudflats, the first having arrived on their southward passage in July. Black Scoters, Surf Scoters, and Red-necked Grebes have already appeared along coastal waters. Much of the warbler migration will occur in September and sparrow migration in October.

The fall migration is a gloriously protracted spectacle. Without the need to claim a breeding territory or find a mate like spring migrants, fall migrants show less urgency.

The number of birds that participate in the fall migration in North America is staggering. I have seen one estimate of five billion birds moving southward on our continent.

Some migrations are relatively modest undertakings. For instance, the Common Loons that nest on our lakes need only migrate eastward to the ocean to spend the winter. Ruby-crowned Kinglets may only migrate as far south as Pennsylvania or eastern New York for the winter.

With the Olympics still fresh in our minds, considering the most impressive bird migrants seems appropriate. In the past few years, I have written about two of the most amazing species of migrating birds. Both Semipalmated Sandpipers and Blackpoll Warblers fatten along coastal portions of northeastern North America and then embark on a non-stop flight over the ocean of some 2000 miles to get to their South American wintering grounds.

Once these birds get south of the 30th parallel, the northeast trade winds help to propel them to the northeastern shores of South America but their migration is still stunning. These birds cannot stop to rest on the water and cannot feed along the way. They have to pack all the fat they will need to fuel their flight before they depart. These migrations require three to four days of non-stop flight.

But, the North American species that covers the most distance in migration is the Arctic Tern. Members of this species breed in the Western Hemisphere from Greenland at a latitude of 84 degrees south to Cape Cod. Their fall migration takes them to the edge of the pack ice in Antarctica. That requires a flight each fall of 12,000 miles!

Unlike the Semipalmated Sandpipers and Blackpoll Warblers, Arctic Terns can feed along their way since they dive for fish from the air. They can also rest on the surface of the ocean. However, 12,000 miles is an awfully long distance to cover in just a couple of months. The advantages are significant; Arctic Terns experience longer periods of daylight than any other species of bird in the Western Hemisphere.

When the Antarctic summer starts to wane in March, the Arctic Terns retrace their migration back to their northern breeding grounds. The record life span for an Arctic Tern is 34 years. The wings of this bird propelled the bird over 800 million miles in its lifetime. That feat is worthy of a gold medal.

The Life of the Skies

I’ve just finished reading The Life of the Skies: Birding at the End of Nature by Jonathan Rosen and enthusiastically recommend the book.

Describing the book is not easy; perhaps, the best way to describe the book is a meditation on birding at the beginning of the 21st century.

Rosen is a novelist and editor of Nextbooks who took up birding as an adult. Central Park, near his New York City apartment, is one of his favorite haunts although he has traveled broadly to pursue his birding passion.

Rosen interweaves several birding narratives in his book including ones on his efforts to see an Ivory-billed Woodpecker, visiting threatened birding hotspots in Israel along with historical accounts of John James Audubon, Henry David Thoreau and Alfred Russel Wallace, a contemporary of Charles Darwin who independently arrived at the concept of natural selection.

References to poetry appear often throughout the various chapters including poems by Robert Frost, Walt Whitman, Emily Dickinson and Wallace Stevens. He also frequently quotes the writing of Edward O. Wilson, the Harvard professor who is one of the most articulate defenders of the need to conserve the diversity of life on earth.

I found Rosen’s analysis of Robert Frost’s poem, The Ovenbird, to be particularly moving. Written around 1910, this poem is a lament for nature that is lost but still expressing a thread of hope for conservation.

The Life of the Skies explores the relationship between wild birds and humans and the scientific, spiritual and emotional ways that birding is important for humans. I thoroughly enjoyed this provocative book.

[Originally published on September 6, 2008]

For the Birds: Bird Phylogeny Revised

The Swedish naturalist, Carl Linnaeus (1707-1778), developed the system of classification that biologists use today to order the rich diversity of life on earth. Linnaeus gave every species a two-part name, denoting the genus and the species of that organism. A genus contains a number of similar but distinct species. Genera (the plural of genus) are combined into families, families into orders, orders into classes and classes into divisions or phyla.

Linnaeus classified organisms based on their morphological similarity. Species belonging to the same genus are generally more similar to each other than they are to members of their own family that are in different genera.

A classification based on similarity of structure runs into two problems. First, two closely related species may diverge from each other over time and appear to be quite different. Second, distantly related species may converge on similar morphologies over time and thus be mistakenly placed in the same genus or family. As one example, Linnaeus placed the barnacles and the mollusks (snails, clams and their relatives) in the same group because all have a hard shell made of calcium. By looking at the early development of these organisms, biologists came to realize that barnacles are crustaceans and therefore more closely related to shrimp, lobsters and crabs.

Charles Darwin held the view that our classification system of life on earth should be a huge family tree, reflecting the relatedness of organisms. Understanding the relationships of the higher groups (orders, classes and phyla) is difficult based solely on morphology. Spirited arguments among biologists in the scientific literature about the relationships of these higher groups are common.

The analysis of DNA gives us a new way to develop the tree of life in the way Darwin envisioned. DNA is the molecule that ultimately determines the way an organism looks and behaves. The idea behind DNA comparisons is straightforward. More closely related species should have very similar DNA while more distantly related species should have more differences in their DNA.

For birds, the Yale biologist Charles Sibley, working in the 1970’s and 1980’s with his colleague Jon Ahlquist, were the first to use DNA comparisons to examine how the higher groups of birds were related. Their results were groundbreaking.

Sibley and Ahlquist used a technique called DNA hybridization. DNA is a double-stranded molecule with one strand being the mirror image of the other. By heating DNA, the double strands separate. Sibley and Ahlquist recombined single strands of DNA from two species to make hybrid DNA and determined how closely the two strands fit together. Species that made tight DNA hybrids were considered to be closely related.

Their many experiments produced a number of surprising results that are reflected in the current classification scheme used by the American Ornithologists Union and in the organization of field guides. For instance, Sibley and Ahlquist showed that the New World vultures are properly classified with the herons, not with the hawks and falcons. Vireos are not closely related to warblers as formerly thought but rather closer to the crows and ravens.

It is now possible to analyze DNA in much greater detail than Sibley and Ahlquist could do with their hybridization studies. Biologists can determine the sequence of the four molecules (called nucleotides) in DNA. Human DNA has three billion nucleotides; that’s a lot of information to compare!

As an example of the power of this approach, humans and chimpanzees have DNA that differs by less than 1%. Our DNA is slightly less similar to that of gorillas and even less similar to orangutans. So using DNA comparisons, we know that chimpanzees are the closest living relatives of humans and gorillas are the next closest of the great apes to us.

A recently published paper by Shannon Hackett and colleagues in the journal Science presents the results of DNA sequence comparisons for 169 species of birds, representing all of the major groups of birds. Like the work of Sibley and Ahlquist, many surprising relationships were found. We can expect the order of birds in our field guides and checklists to change to reflect his new work.

Here are some of their major findings. The perching birds (the passerines) are most closely related to the parrots! Falcons are closely related to these two groups of birds but not to the hawks and eagles. Thus, the falcon family and the hawk family have converged. The closest relatives of the penguins are the albatrosses. Unlike Sibley and Ahlquist, the new papers shows New World vultures are closest to the hawks and eagles. You can see further results of this important paper at: http://whozoo.org/birds/birdphylogeny.html

[Originally published on August 30, 2008]

For the Birds: Plover and Sandpiper Feeding

Shorebird migration is underway. In the past week, Maine birders have found Greater Yellowlegs, Lesser Yellowlegs, Short-billed Dowitchers, Semipalmated Sandpipers and White-rumped Sandpipers. Most of these species nest in the Arctic. The window of opportunity for nesting in the Arctic is short so it is not surprising that these birds have departed the high latitudes already.

For many Arctic-nesting shorebirds like the Semipalmated Sandpiper, two pulses of migration are seen. The first pulse, the one we are beginning to see now, is almost entirely adult birds. These birds have left their young on the breeding grounds, in many cases before the young have even learned to fly.

Shorebirds do have precocial development; they hatch with feathers and can forage for food shortly after hatching. So, adults departing early is really not a form of child neglect. The young will eventually learn to fly and then depart on their migration. These juvenile birds, arriving in Maine mostly in September, constitute the second pulse of the migration.

Most migratory birds have their migration route hard-wired rather than having to learn a migration route. That becomes obvious with birds like Semipalmated Sandpipers who do not have mom or dad to show them the way. Mistakes do occur, however. The chance of a first-year sandpiper showing up at some unexpected location is greater than the chance of an adult appearing at the same place.

To fuel their migration, shorebirds have to feed gluttonously along the way. I think it is fascinating to watch how different species of shorebirds feed.

Let’s start with the plovers. A careful look at a plover will indicate that its eyes are quite large relative to its head size compared to most sandpipers. These large eyes suggest that vision is of primary importance in finding food. That is indeed true.

The foraging behavior of plovers can be called run-and-peck. A plover on an intertidal flat will look for movements at the sediment surface indicating the presence of a crustacean or polychaete worm. It will then run to the location and attempt to grab the prey item.

Keep an eye out for a behavior of Black-bellied Plovers called foot trembling. A plover will stand on one leg and vibrate the other food right at the sediment surface. This trembling appears to set up vibrations that a bloodworm or other invertebrate predator interprets as a possible prey item. The bloodworm comes to surface looking for dinner and finds that it is on the menu of the plover!

Sandpipers, the other major group of the shorebirds, rely on touch to find their food. The bill of a sandpiper is richly endowed with touch receptors, particularly at the tip. A sandpiper probes the sediment until the touch receptors detect the movement of a small invertebrate and the bill clamps down on the prey item.

Particularly for long-billed sandpipers like dowitchers, a significant amount of energy would be required to open the long bill while it was stuck in several inches of mud. To make opening the bill easier, sandpiper bills are rhynchokinetic. That is, the can open the tip of the bill without having to open the portions of the bill closer to the skull. You can see a nice picture of this behavior at: http://birdblog.merseyblogs.co.uk/archives/2006/07/its_called_rhyn.html

Sandpipers on an intertidal flat occur in characteristic spots. Dowitchers and Stilt Sandpipers with their long bills wade in up to their bill and probe rapidly into the sediment. Their probing is often quite rapid and is referred to as stitching (like a sewing machine). Dunlins with somewhat shorter bills tend to forage right at the water’s edge. Short-billed sandpipers like the various peeps feed above the tidemark.

One advantage sandpipers have of using touch rather than sight to find food is that sandpipers can feed at night. Nocturnal feeding is particularly valuable during migration when sandpipers are trying to pack on fat as quickly as possible.

Some years ago, I determined the predation rate of Semipalmated Sandpipers in the Bay of Fundy on their favored prey, the small crustacean Corophium volutator by videotaping foraging birds. Corophium is about 3/8 inch long. I found that each sandpiper was taking about 17,000 Corophium each day. That goes a long weight toward explaining how these sandpipers double their weight in only two weeks.

Recent research has shown that Western Sandpipers acquire a majority of their energy by consuming biofilms. A biofilm is a thin layer of bacteria, detritus and sediment held together by a glue-like material secreted by microalgae and bacteria. Biofilms may be important in the diets of other shorebirds too.

[Originally published on August 23, 2008]

For the Birds: Ontario Conservation Easement

Birds often find humans to be rather undesirable neighbors. In the last three columns, I wrote about the decline of some grassland birds and some efforts to stop the decline. One of the most effective conservation tools that environmental managers have at their disposal is habitat protection. In Maine, remaining grasslands like the Kennebunk Plains and the Wells Barren are now protected, thanks to the work of The Nature Conservancy and other organizations.

But grasslands are not the only habitats we should be worried about. The notion that we have enough forest in Maine and elsewhere at northern latitudes is shortsighted. We know that highly fragmented forests may not be acceptable habitat for a number of breeding birds. Species like Barred Owl, Ovenbird and Scarlet Tanager seek nesting territories within large tracts of unfragmented forest. Highly fragmented forests simply will not do.

The government of the province of Ontario recently announced some great news for conservation, including a great boon for birds that breed in the boreal forest. The Premier, Dalton McGuinty, proudly revealed that the Ontario Government will protect at least half of Ontario’s boreal forest. The protected area will include 86,900 square miles of boreal forest. That area is nearly three times the size of Maine! Corridors between large areas of forest help to minimize the effects of forest fragmentation as unprotected areas are developed and altered.

The decision was primarily impelled by a letter sent to the Canadian government on behalf of over 1500 scientists worldwide, who strongly recommended that 50% of Canada’s boreal forest be protected. These scientists identified the 1.4 billion acre Canadian boreal forest as one of the largest intact forest and wetland ecosystems remaining on earth.

The boreal region is one of the last truly wild spaces on earth. It is home to over 200 sensitive species of animals, such as polar bears, wolverines and caribou. Many of these species are threatened or endangered. The protection of this area will be a huge step in preventing a decline in the biodiversity of the region.

Preserving large tracts of this boreal region is necessary because of increasing pressure from corporate logging and mining concerns. Oil and gas operations represent threats to the habitat as well.

Over 300 species of birds are found in the boreal forests of North America. This forest ecosystem provides breeding habitat for over 40% of the population of 21 warbler species. Nearly 100 species of birds have the majority of their population in the boreal forest during the summer. Ontario’s landmark decision is reason to cheer for all birders.

The protection of this large tract of forest will help combat global warming. The absorption of carbon dioxide by the boreal forest trees is a significant carbon sink.

Altruism

Altruism is the term that biologists use to describe selfless behavior. Although examples of altruism abound for humans, biologists are skeptical of claims of altruistic behavior in other species. After all, much of the behavior of an organism can be understood in trying to reproduce and hence perpetuate one’s genes. Helping other organisms at one’s own expense is hardly the way to get your genes into the next generation.

Some animal behaviorists think that selfless behavior can be worthwhile as long as it is reciprocal. Two organisms might strike a bargain where each agrees to share food if the other is unable to find food. This reciprocal altruism seems like a win-win situation, right? The problem is that cheaters win. I might be more than happy to eat some of your food when I have none but I may selfishly choose not to share when I have food and you do not.

Some recent work on Pied Flycatchers, a species found in Eurasia, has shed some light on how cheaters in system of reciprocal altruism might be punished. Pied Flycatchers will mob a predator, jointly assaulting the predator to drive it away. When a predator is seen, a Pied Flycatcher will give an alarm call to attract other Pied Flycatchers to join the mob. Cooperation usually results in the predator being chased away.

However, some Pied Flycatchers are cheaters. They may not respond to an alarm call and help mob the predator. Experiments done in the field showed that when a Pied Flycatcher that did not help mob a predator sees another predator and gives the alarm call, the birds that mobbed the first predator refuse to help the cheater. It’s a case of “You didn’t help us mob earlier so we are not going to help you now – good luck chasing away that hawk on your own”. So, this study has identified a case of reciprocal altruism where cheaters do not prosper.

[Originally published on August 9, 2008]

For the Birds: Upland Sandpiper and Eastern Meadowlark

This column is the last of three on grassland birds in Maine. In today’s column, we will take a look at Upland Sandpipers and Eastern Meadowlarks, both of which require grasslands for nesting.

Like the American Woodcock, the Upland Sandpiper is a shorebird that has adopted a purely terrestrial lifestyle. Don’t look for Upland Sandpipers foraging on intertidal mudflats with Sanderlings, Semipalmated Sandpipers, Greater Yellowlegs and other members of the sandpiper family. Rather, Upland Sandpipers prefer rather dry habitats with a dearth of trees. Grasslands are their natural breeding areas although lowbush blueberry barrens can serve as nesting sites as well. Grassy areas at airports also provide nesting habitat.

An Upland Sandpiper is a large sandpiper with a long bill. Its neck is markedly thin and its head seems to be too small for its body. The plumage consists of black, brown and tan feathers that make the bird cryptic in the tall-grass habitats it prefers.

The call of the male is a sound that will stick with you. Many people will not recognize the eerie whistle of the male as coming from a bird. Efforts to represent the whistle in human syllables include “whooooleeeeee, wheeelooooo-ooooo”. To some, the call sounds like a “wolf whistle”.

The greatest abundance of nestling Upland Sandpipers is found in the Dakotas, Nebraska and Kansas. Populations can be found westward to the Rocky Mountains and eastward, occurring patchily in New England and some of the Mid-Atlantic States. These birds winter on the pampas and other grassland habitats in South America.

In most nesting areas, Upland Sandpipers have suffered at the hands of humans. First, early European settlers killed them for food as well as collected their eggs. Later, market hunters took even more. But, the most devastating effect caused by humans was the plowing of the tall-grass prairies to plant crops. Breeding Bird Survey data show that numbers of Upland Sandpipers continue to decline over most of its breeding range, North Dakota being the only state where Uppies are holding their own.

The last species we will consider is the Eastern Meadowlark, a species associated with farmlands. Before European settlement, Eastern Meadowlarks were dependent on native grasslands for habitat. Unlike the Upland Sandpiper, meadowlarks have proven to be adaptable, readily nesting in pastures.

Eastern Meadowlarks are found broadly throughout eastern North America. Their northern limit occurs from Minnesota eastward through Ontario and into the Maritime Provinces. Meadowlarks can be found throughout the states south of this line. They even extend discontinuously throughout Central America.

In most of their range, Eastern Meadowlarks are non-migratory. The meadowlarks in New England and other northern states withdraw in late fall to warmer portions of the species’ range. Meadowlarks usually return to Maine in late March to April.

Eastern Meadowlarks are distinctive birds. They have a bright yellow breast with a V-shaped black patch on the upper breast. The description of a yellow V-necked sweater is certainly apt. On the side of the face below the eye, a whitish stripe, the malar stripe, is distinctive. The Western Meadowlark, which overlaps with Eastern Meadowlark in some parts of their ranges, is almost a dead ringer for the Eastern. However, the malar stripe of the Western Meadowlark is mostly yellow.

The upper side of the Eastern Meadowlark is mottled gray, black and brown, allowing the bird to blend in well with its grassland habitat. The outer tail feathers are white, making these feathers a good field mark for a flying meadowlark.

Like other grassland birds, Eastern Meadowlarks will be detected first by their voice. The song of this species is a series of clear, slurred whistles. Some ornithologists have tried to capture the cadence of the song as “song of the earth”.

Despite their use of agricultural fields for nesting, Eastern Meadowlarks are showing alarming declines throughout much of their range. Part of this stems from a reversion of old farms back to forests. Human encroachment to breeding areas also plays a role in the decline of these birds.

As an overview, we have seen that grassland birds are declining through much of their range. While we should be concerned, there is some reason for hope. In recent years, the science of landscape ecology has matured. Landscape ecologists study how variation in habitat at large scales affects the distribution of organisms. Landscape ecologists understand the importance of interconnected reserves, of conserving habitat near already protected habitat and of evaluating the conservation potential of available tracts of land. Active management of grasslands will need to be continued to prevent forests from taking over.

[Published on July 26, 2008]

For the Birds: Grassland Sparrows

This column is the second of three on grassland birds in Maine. In today’s column, we will take a look at three sparrows (Savannah, Vesper and Grasshopper) that require grasslands for nesting. In the next column, I’ll discuss the Upland Sandpiper and Eastern Meadowlark and end with some of the conservation challenges of these habitats.

The three sparrows in today’s column are more often heard then seen so learning to recognize them by song is the best way to find these somewhat shy birds.

The Savannah Sparrow is the most common of the three. Its breeding range covers most of the northern two-thirds of North America, extending into the arctic tundra. It is a migratory breeder in most parts of its range. During the winter, Savannah Sparrows withdraw to the southern tier of the United States and into much of Central America.

The species was named the Savannah Sparrow by Alexander Wilson, a contemporary of Audubon. Wilson collected a specimen in Savannah, Georgia and honored this charming southern city by naming a sparrow after it.

The song of the Savannah Sparrow has a distinctive buzzy quality. The song typically begins with a few short notes, then a buzzy trill and a final note or two of lower pitch. The song carries well, particularly the trill and final notes. A singing male can usually be seen singing from a grass stem or short shrub.

Visual identification of this species is straightforward. A Savannah Sparrow has a streaked breast like a Song Sparrow. The Savannah Sparrow’s streaks are less bold than those of a Song Sparrow and typically do not coalesce into a dot as in most Song Sparrows. The best field mark is the yellow line above the eye that is especially conspicuous in front of the eye.

During the breeding season, Savannah Sparrows mostly feed on insects. Outside of the breeding season, they switch to a diet of seeds they are able to find on the ground.

Like the Bobolinks discussed in the last column, a male Savannah Sparrow may have more than one female partner. The insect abundance in a grassland or meadow is abundant enough to allow a male to help feed two clutches of nestlings.

Vesper Sparrows have a broad distribution in North America, not quite rivaling the broad range of the Savannah Sparrow. Vesper Sparrows nest across the middle third of our continent and winter in the southern tier of states south into Mexico.

The song of the Vesper Sparrow has a distinctive beginning of two to four long clear notes followed by a downslur and then a series of flute-like trills, first rising in pitch and then falling. Vesper Sparrows sing throughout the day but continue to sing in the evening after most birds have ceased to sing. Those evening songs are the reason the bird is called the Vesper Sparrow.

The dependence of Vesper Sparrows on grassland habitats is doubly reflected in its scientific name, Pooecetes gramineus. Pooecetes means “grass dweller” and gramineus means “fond of grass”. In Maine, grasslands and blueberry barrens are the best places to find this sparrow.

The Vesper Sparrow is a rather large sparrow. These sparrows have a streaked breast and distinctive white outer tail feathers. Some of the wing coverts are rufous in color, giving rise to the older common name of Bay-winged Bunting.

We believe that Vesper Sparrows were rare in the east before European settlement. The clearing of forest for pastures allowed Vesper Sparrows to increase in eastern North America. The species is declining in the east now because of the reversion of so many farms to forest.

Grasshopper Sparrows are the least common of the three grassland sparrows. They breed broadly throughout the eastern two-thirds of the United States but are usually found in low numbers. Their populations have declined in many portions of their range because of the destruction of grasslands and prairies these birds require for nesting.

The common name of this species stems from its insect-like songs. Male Grasshopper Sparrows are unusual among sparrows in that they sing two distinctly different songs. Their Primary Song consists of one to three high-pitched notes followed by an insect-like trill. It can be described as tsick, tsick, tsurrrrrrr. This song is used to repel other males from its territory. A second song, the Sustained Song, consists of a more musical series of short buzzy notes given either from a perch or in flight to attract a female.

The pronounced flattened head, the large bill and upper orange breast make the Grasshopper Sparrow easy to identify once sighted.

[First published on June 28, 2008]

For the Birds: Bobolinks

A suite of birds collectively called the grassland birds nest in New England. This group of birds includes the Upland Sandpiper, Savannah Sparrow, Vesper Sparrow, Grasshopper Sparrow, Eastern Meadowlark and Bobolink. Wildlife biologists are concerned about this group of birds because their populations are declining in New England, including our Maine populations.

Grassland habitats are rather limited in New England and have invited development into farms or towns because tree cutting is not required adapt the line for human uses. Fortunately, grassland birds are adaptable and often nest in hayfields or blueberry barrens. However, many hayfields in Maine are no longer maintained and are reverting to forest. We have much more forested land now in Maine than we did in 1900. Thus, the decline of their required habitat helps explain the decline of these grassland birds.

Today’s column is the first of three on the grassland birds of Maine. We’ll start with one of the most beloved birds of Maine, the Bobolink.

With their beautiful plumage (mostly black with white on the back and wings, and a yellow patch on the back of the head and nape), male Bobolinks are strikingly handsome birds. Some waggish authors have described them as having tuxedos on backwards.

The female is nondescript, brown on the uppersides with streaking and yellowish underneath. This plumage makes them nearly impossible to see in a grassy field.

The male’s song is equally distinctive: a long, bubbly series of metallic notes. A student of mine, an obvious Star Wars fan, said the song sounds like the robot R2D2! The Bobolink song has inspired poetry. The American poet, William Cullen Bryant, based his poem “Robert of Lincoln” on the song of the Bobolink.

The breeding range of Bobolinks extends across the northern tier of the United States from Maine to Washington as well as the southern portion of the Canadian provinces.

Bobolinks winter south of the equator in South America, The wintering habitat is the grasslands known as the pampas in southwestern Brazil and Argentina. Each year, a Bobolink makes a round-trip of 12,000 miles. We know of one banded female that lived to be nine years old. Presuming she made the trip every year, she traveled the equivalent of circling the globe at the equator four times.

Orientation and navigation have been fairly well studied for Bobolinks. Researchers have found that the primary cue for navigation in Bobolinks is the earth’s magnetic field.

Bobolinks arrive in central Maine by the second week of May. Males are conspicuous as they stake out territories and await the arrival of the females. When a female passes overhead, a male will perform an aerial song display to attract the female’s attention. If the female lands, the male will go through a series of courtship behaviors to court the female. These behaviors include a low circle flight on stiffly held wings and an abrupt drop to a low perch or the ground. When the male drops, he holds his wings in a shallow V (like the gliding silhouette of a Turkey Vulture) and gives a few buzzy notes, dangling his legs on the descent. When he touches the ground, he may hold his wings in the shallow V for several seconds.

A female is slow to choose a mate. A male may have to perform this elaborate courtship sequence five times a minute for a half-hour or more. A pair bond is formed when the female leads the male on a long chase, flying for up to six minutes.

Bobolinks are examples of polygynous birds; a male may have more than one female on his territory. The frequency of polygyny seems to be related to habitat quality. In high quality habitats where food is easier to find, a male frequently has two or more mates. In lower quality habitats, single females are typically found with the males. In Wisconsin, over half a population of males had at least two mates and one male had four mates. On the other hand in New York, fewer than 15% of the males had more than one mate.

Nests are always made on the ground in dense vegetation. The nest is usually located at the base of herbaceous, non-grassy vegetation like goldenrods or clover. The female chooses the nest location and builds the nest in one or two days.

A female typically lays five eggs although as many as seven can be laid by some females. Both the female and the male feed the young. Even a male with multiple mates participates in feeding although most assistance may be given to his primary mate.

[First published on June 14, 2008]

For the Birds: Red-eyed and Philadelphia Vireos

Red-eyed Vireos have returned from their South American wintering grounds. One of the most common songbirds in North America, the Red-eyed Vireo’s song is a distinctive but somewhat plain series of two- and three-note phrases. Some authors render the song in human terms as “here-I-am, where-are-you, over-here, in-the-tree” that will resonate with anyone who has heard a Red-eyed Vireo singing. Red-eyed Vireos are energetic songsters, singing throughout most of day with rates as high as 85 phrases/minute.

The Philadelphia Vireo occurs in northern New England and much of southern Canada. This vireo closely resembles the Red-eyed Vireo but has a less distinct line above the eye and has a yellow wash on the underparts. The Philadelphia Vireo is also smaller, averaging 12 grams in weight to the 17-gram weight of a typical Red-eyed Vireo. Both species can be found in the same deciduous woodlands.

Most nesting male songbirds defend their territories against other males of its species. If you play a recording of a Yellow Warbler in the territory of a Yellow Warbler, the male will quickly come toward the source of the sound and look to chase off the unwelcome intruder. However, playing a tape of the song of a Black-throated Blue Warbler or a Chestnut-sided Warbler will produce no reaction by the Yellow Warbler. In general, male songbirds defend their territories against members of their own species but not against members of other species.

The two vireo species above provide an exception to this rule. Red-eyed Vireos and Philadelphia Vireos defend their territories against their own species and against the other species. In other words, both vireos show interspecific (between-species) and intraspecific (within-species) territoriality.

The song of the Philadelphia Vireo is very similar to the singsong phrases of the Red-eyed Vireo song. Even highly experienced birders pass off singing Philadelphia Vireos as the more common Red-eyed Vireos. The reason for the similarity will soon be apparent.

In northern New England forests, insect prey may become quite hard to find during the breeding season. Because both vireos eat largely the same species of insects, there is an advantage for a territorial vireo to keep a member of its own species and members of the other vireo species away from its food sources.

In most cases, the vireos avoid direct confrontations over the boundaries of a territory. Instead, a territorial bird proclaims his ownership of a territory by singing from perches throughout his territory. Similarly adjacent territory owners sing throughout their territory. The neighboring birds recognize unseen but real boundaries, avoiding physical interactions.

In the case of actual fighting between the two vireo species, the smaller Philadelphia Vireo usually comes out on the short end. One observed fight involved three minutes of violent contact, wing beating and pecking, with the larger Red-eyed Vireo winning the battle.

The problem the Philadelphia Vireo has is how to maintain exclusive ownership of a territory, defending against a larger and stronger Red-eyed Vireos that may be trying to expand his territory to find scarce food. Philadelphia Vireos have solved the problem by becoming a social mimic. These birds mimic the song of the Red-eyed Vireo.

Play-back experiments have shown that Red-eyed Vireos cannot tell the difference between a Red-eyed Vireo song and a Philadelphia song. No wonder birders have trouble telling the two species apart by song! On the other hand, Philadelphia Vireos can distinguish between a Philadelphia Vireo song and a Red-eyed Vireo song.

Red-eyed Vireos assume that a neighboring Philadelphia Vireo is a Red-eyed Vireo and accept it grudgingly as a neighbor. If the Red-eyed Vireo only knew its neighbor was the meek Philadelphia Vireo, the latter could be evicted. Philadelphia Vireos mimic the song of the Red-eyed Vireo to level the playing field; it’s a case of brains over brawn.

Computer analysis of the songs of these two species reveals that Red-eyed Vireos never sing the same phrase twice in succession. Philadelphia Vireos, occurring in the absence of Red-eyed Vireos, may sing the same phrase twice before a new song is sung. However, in the presence of a Red-eyed Vireo, the Philadelphia Vireo never gives identical consecutive phrases, indicating that the species actively mimics the Red-eyed Vireos. Pretty clever birds!

[First published on May 31, 2008]

For the Birds: Spring Migration; Hog Island Camps; Maine Butterfly Survey

Migration

The marvelous spectacle of spring migration is here. Soon, the Black-billed Cuckoos, Blackpoll Warblers and Yellow-bellied Flycatchers will arrive in good numbers. The appearance of these late-arriving species signals the end of the spring migration.

Today, I want to consider why birds migrate. Each spring, several billion birds stream into North America from Caribbean islands, Central America and South America where they have spent the winter. Why do so many birds undertake these arduous migrations? The benefits must exceed the costs. What are the benefits migrating breeders receive?

To answer these questions, we have to understand both why birds migrate north to breed and why they leave their northern breeding grounds to return to tropical or subtropical areas. The explanations stem from the fact that the earth is tilted on its axis.

Let’s start with equatorial regions. Despite the tilt of the earth, equatorial regions have twelve hours of daylight each day. As one proceeds north, the length of day and night becomes unequal. When the northern hemisphere is tilted toward the sun, we have summer and temperate regions have day lengths that increase as one moves toward the North Pole.

The long summer days mean that plants can photosynthesize for sixteen hours or more each day, longer than plants at the equator. So during the northern summer, plant production spikes, providing food for insects that in turn provide food for birds. During the northern summer, food availability in temperate regions may exceed that of tropical regions. Birds migrate to the north to take advantage of the summer flush of food. The further north one goes, the longer the day length and bigger the spike in plant growth.

All good things must come to an end and the movement of the earth around the sun ultimately leads us to autumn with ever-shortening day lengths. Plant production decreases as light becomes less available and temperatures fall. Insect abundance declines. Many migratory breeding birds depend on insects so must leave for southerly areas to avoid starvation.

The cost of migration is more than paid for by the abundance of food in the summer at higher northern latitudes. But not all tropical birds migrate. What are the costs and benefits of staying put? The benefit is the energy saved by not migrating. The cost is that competition for food is very high in the tropics and destruction of nests by predators is very high. Tropical birds typically have multiple nests each season with a modest number of eggs, most of which are doomed to failure.

Hog Island Audubon Center

A landmark of environmental education since 1936, Hog Island Audubon Center’s residential programs educate, adults, children and families about coastal wildlife in Maine. The sessions are based on a 330-acre island in midcoast Maine’s Muscongus Bay. The sessions are led by some of the world’s most respected naturalists and environmental educators. You can find more information about their offerings at: http://www.maineaudubon.org/explore/camp/hi_overview.shtml

I want to call your attention to a new session called Family Birding Adventures geared for families with kids between the ages of six and thirteen. One of the highlights of the week will be a trip to Eastern Egg Rock to see nesting Atlantic Puffins. The session will be led by Jason and Laura Guerard, naturalists from the Cape May Bird Observatory. Jason and Laura met on Hog Island and Jason later proposed to her there. For more information, visit the website above or call (888) 325-5261 ext. 215.

Maine Butterfly Survey

The Maine Butterfly Survey, a five-year project to map the distribution and abundance of the butterflies and skippers of Maine, has begun its second year. This project relies heavily on volunteers. The first year yielded over 1500 records (specimens or photographs). Volunteers established four new state records and a large number of county records in the first year of the project. Two volunteers photographed Pipevine Swallowtails in late September 2007. These two records represent the first records of the species since 1907. You can see all of the 2007 records at the MBS website: http://mbs.umf.maine.edu/

As the Volunteer Coordinator for the project, I would like to encourage you to participate in the project. All participants are asked to attend a training workshop. Each workshop participant will be given equipment, a handbook and voucher forms. The last 2008 workshop will be held on Saturday, June 21 at Colby College in Waterville. The workshop will begin at 9:30 and conclude around 2:30. Lunch will be provided. If you are interesting in attending the workshop, please email me to reserve a spot. Enrollment is limited.

[originally published on May 17, 2008]

For the Birds: New Bird Books for Beginning Birders

The spring migration is perhaps the most exciting time of year for North American birders. After a long Maine winter, the sounds of the first Eastern Phoebes and Red-winged Blackbirds and the sights of colorful warblers hold the promise of a glorious Maine summer. There is nothing like a spring birding excursion to hook a novice on birding.

Two books geared for beginner birders have recently appeared. One is meant for adults and one for kids. I’ll review the two books in today’s column. Perhaps, you have a friend or family member who might appreciate a copy of one of these books.

Finding Your Wings, written by Burton Guttman, is a different kind of book in the Peterson Field Guide series. This book is really a workbook designed to help a person new to birding to learn how to really look at birds how to identify them. Along the way, a diligent user of Finding Your Wings will learn much about bird behavior, classification and the etiquette of birding.

This workbook is designed to be used in conjunction with a field guide of North American birds. The workbook is specifically written to accompany either Roger Tory Peterson’s A Field Guide to Birds of Eastern and Central North America or A Field Guide to Western Birds. However, any North America field guide can be used in conjunction with Finding Your Wings.

The workbook begins with basic principles and skills of birding, continuing with an overview of the major bird orders and then more detailed descriptions of the topography of birds. Other chapters deal with molting, identifying birds in flight and learning to identify birds by their songs or calls. The book concludes with six chapters on groups of birds that pose particularly challenging identification problems. Bird groups covered include hawks, shorebirds, gulls and sparrows.

The content of the book sounds like standard fare for a birding book. The unusual, and I think innovative, aspect of Finding Your Wings is the activities and quizzes that fill the book. Doing the activities and taking the quizzes is key to getting the most out of the workbook.

Four kinds of activities are used in the workbook. Indoor Exercises require the reader to refer to a picture provided or pictures in a field guide to answer questions. A reader might be asked to look at the account for a Clay-colored Sparrow and then write down a description of the head of the bird. In so doing, the reader would learn the names of distinctive markings like the supercilium, auricular stripe and malar stripe. Answers are provided at the end of the book.

Field Exercises require the beginning birder to make observations in the field, such as determining the wing beat rate of different birds. Quizzes allow readers to test their knowledge gained from the Indoor and Field Exercises. Finally, several Games are described that are great for social learning.

The second book, also in the Peterson Field Guide series, is called The Young Birder’s Guide to Birds of Eastern North America by Bill Thompson III. This field guide was developed with the advice of Thompson’s 11-year old daughter and other members of her fifth-grade class. The field guide is designed to be used by kids on their own.

The field guide begins with the usual generic information on birding: binoculars, bird morphology, field guides, birding clothing. One section seeks to convince youngsters that birding is cool and that they should not be self-conscious about going birding.

The bulk of the book is the description of 200 species of common birds found in eastern North America. A page is devoted to each species. Of course, the amount of text one expects in a typical field guide is reduced in this “for kids” guide. Each page has one or two color photographs and a range map, covering all of North America. A line drawing is provided for each species, showing some interesting behavior. For instance, the drawing of the Hermit Thrush shows the distinctive behavior of these birds in raising the tail rapidly and then slowly letting it fall to a normal position. Each species account has five text sections. Look For provides brief information on the characteristics used to identify the species and Listen For gives a description of the vocalizations. The Remember section is used to emphasize distinctive identification features or behaviors. Find It describes the habitat of each species. Finally, a WOW! section describes a neat feature of a species such as the courtship flight of the Scissor-tailed Flycatcher or 1800-mile non-stop migratory flight of Brant.

[Originally published on May 3, 2008]

For the Birds: Human-caused Bird Extinctions

Tuesday is Earth Day. I hope you will take the time to think about how you can make a difference in the protection and conservation of our planet’s organisms and resources. Go to http://ww2.earthday.net/ to find out about Earth Day activities in your local area.

In the last column, I wrote about sources of bird mortality. Many birds die because of direct human activities (for example, overhunting) or indirect effects of our use of the earth (for example, habitat destruction and pollution). Today, we will consider birds that have been pushed over the brink to extinction because of human activities. This sobering topic should make us all take Earth Day even more seriously. Extinction is forever.

Over the past 500 years, over 140 species of birds become extinct. With the exception of only about a dozen species, these birds were driven to extinction by human activities. Of the roughly 11,000 existing birds species, 1200 are currently in danger of extinction.

The majority of these extinctions occurred on oceanic islands. Many of these islands are small so population sizes are never very high. Many birds on oceanic islands become flightless over time and are therefore not able to escape from human hunters. Finally, birds on oceanic islands with few predators are often fearless in the presence of humans or introduced predators.

The Dodo provides an instructive case study for the extinction of island bird species. This species belongs to the order of birds that includes the pigeons and doves. The Dodo was flightless and most individuals were about three feet tall, weighing more than 40 pounds. They were found only on the island of Mauritius, an island off the coast of Madagascar. Dodos were fruit eaters in the Mauritian forests.

Dodos were certainly extinct by 1681, only 174 years after Europeans first became aware of them. Their demise began with the colonization of Mauritius by Dutch settlers around 1600. Although Dodos would have been easy for humans to kill, journals of Mauritian visitors indicate that the meat of Dodos had an unpleasant flavor and was quite tough. Humans hunted other birds, like the Red Rail, for food. The dramatic decline of the Dodos was rather caused by the cats, pigs and monkeys (Crab-eating Macaques) that the Dutch settlers brought with them. These introduced animals took the eggs or nestlings from the Dodo nests on the ground. By cutting forests and hence reducing Dodo habitat, humans accelerated the extinction of the Dodo.

Mauritius and nearby islands were home for 27 species of birds found uniquely on those islands. Today, 24 of those species are extinct. Such is the footprint of human settlement.

Hawaii is notable for a remarkable suite of birds called Hawaiian honeycreepers, found only in Hawaii. Related to our finches, the honeycreepers have not fared well with human development of the Hawaiian Islands. In the past 200 years, ten of the 31 species have been driven to extinction and several others are endangered.

Understanding the causes of extinctions is sometimes difficult. In New Zealand, 25 species of flightless birds called moas existed until about 300 years ago. We know that Maoris colonized New Zealand about 650 years ago and certainly ate moas and their eggs. However, the New Zealand climate has been changing over the past thousand years, reducing the grasslands the moas favored at the expense of expanding forests. How much of the blame for the extinction of the moas should be pinned on humans? We don’t know for sure.

But bird extinctions don’t happen only on islands. We have lost at least three species of North American birds in the past 200 years. We can clearly point an accusing finger at ourselves for two of these extinctions.

The Passenger Pigeon was once the most abundant bird in North America, migrating in astoundingly large flocks. They were colonial breeders, nesting sometimes in groups of 100,000 birds or more. The pigeons were hunted commercially as a cheap food for slaves and the poor. The pigeon population declined slowly from 1800 until 1870. As a result of more sophisticated capture techniques, the Passenger Pigeon population plummeted over the next 20 years with the last major harvest taken in 1896. These pigeons, once numbering in the billions, were hunted to extinction.

The Carolina Parakeet, the only parrot in eastern North America, went extinct because of deforestation and the killing of birds for use in ladies’ hats and for protection of fruit crops.

We know little about the extinction of the Labrador Duck. In all likelihood, the Eskimo Curlew and Bachman’s Warbler are extinct as well with humans having a significant role in their decline.

[originally published on April 21, 2008]

Birds and Cat Mortality

As Earth Day approaches, I want to focus on the negative impacts that humans are having on our bird populations. Under the auspices of the Migratory Bird Treaty Act, 836 species of native North American birds are protected. Of those species, 78 are on the Endangered Species List and 14 more are listed as Threatened. Another 144 are listed as a Bird of Conservation Concern. Collectively, nearly a quarter of our bird species appear to be declining. The situation is probably even worse than we realize because we have very poor population data on many less common birds that are not currently listed as species of concern.

Some birds perish because of natural causes (for example, weather, predation by birds of prey, mammals or snakes, starvation, disease). But an awful lot of bird mortality can be attributed to human activities.

Without a doubt, the most significant impact humans are having on bird populations (and other flora and fauna as well) stems from habitat destruction or degradation. This habitat alteration has complex effects for migratory birds that require particular habitats for wintering, for stop-overs during migration and for nesting. It is hard to precisely gauge the impacts of habitat destruction on our bird populations. But added to deaths from natural causes, habitat alteration may be pushing some birds over the brink to local or even global extinction.

We have better measures of bird mortality from some human-related sources. Collisions of birds with buildings, mostly from flying into windows, claim nearly a billion birds a year. Collisions with cell phone and television/radio towers are responsible for five to 50 million avian deaths a year. Collisions with high tension power lines results in over 100 million bird deaths annually in the United States. Collisions with cars kill 60 million birds a year.

Over-use of pesticides can result in dramatic localized kills of birds. One recent estimate claimed that 72 million birds each year perish from exposure to pesticides. This estimate is surely low because pesticides may act slowly in a bird, resulting in death at a distance from a pesticide hot spot. Pesticides may cause neurological problems for birds, leading to death from starvation.

Cats are a potent source of mortality for birds. They have had devastating effects on some oceanic islands, leading to the extinction of some birds. In North America, we really do not have a good handle on the magnitude of the effects of cats on our birds. A recent study in Wisconsin demonstrated that domestic cats in the countryside kill 39 million birds in that state each year.

A recent article by Victoria Sims and her colleagues published in the journal Diversity and Distributions addresses the impact of cats on birds in urban areas in Britain. Only about 3% of cats in Britain remain indoors at all times.

Controversy reigns in Britain about the impact of cats on bird populations. One study claimed that cats account for a third of the deaths of local bird populations. On the other hand, skeptics argue that no conclusive studies have been done to demonstrate significant impacts of cat predation other than on oceanic islands.

When conducting a predator-prey study, an ecologist often begins by documenting the relationship between predator numbers and prey numbers. One expects to see a negative relationship: when predators are scare, prey density should be high; when predators are abundant, few prey will be found. In the field, such relationships between a cat predator and prey abundance have been found for lions, tigers and lynx. Domestic cats are a bit more complicated because they get some of their nutrition from the cat food that their owners provide.

In the Sims study, bird population numbers were obtained from Breeding Bird Survey (BBS) squares (each 1 km on a side) chosen randomly from across Britain. They focused their attention on 30 squares within urban areas. Within each of these urban BBS squares, they censused cats by door-to-door or telephone surveys.

The ornithologists found a positive relationship between the number of cats and the numbers of individual birds (the more cats, the more birds). This result suggests that cats are not having a significant predatory effect on birds. However, the authors claim that cats may have a strong impact in all of their study squares. The lowest cat density in a BBS square was 132 cats. One might expect to see higher bird densities in an urban study square with no cats. So, this study has shone some light on the controversy of the importance of cat predation on birds but is far from the last word.

[originally published on April 7, 2008]

For the Birds - Maine Butterfly Survey; Short-stopped Migrations

Maine Butterfly Survey

The Maine Butterfly Survey, a five-year project to map the distribution and abundance of the butterflies and skippers of Maine, will kick off its second year this spring. This project relies heavily on volunteers. The first year yielded nearly 1000 records (specimens or photographs). The identification of the specimens is currently being confirmed by Reggie Webster, an expert in butterfly taxonomy.

Two volunteers photographed Pipevine Swallowtails in late September. These two records represent the first records of the species since 1907.

As the Volunteer Coordinator for the project, I would like to encourage you to participate in the project. All participants are asked to attend a training workshop. Each workshop participant will be given equipment, a handbook and voucher forms. The next workshop will be held on Saturday, May 3 at Colby College in Waterville. The workshop will begin at 9:30 and conclude around 2:30. Lunch will be provided. If you are interesting in attending the workshop, please email me to reserve a spot. Enrollment is limited.

The Scientific Method

Science provides us with one of the most powerful ways of understanding our world. The scientific method begins with observation of a pattern and then the creation of one or more hypotheses to explain the pattern. The next step is the collection of either experimental data or observations to try to disprove the hypotheses. If one hypothesis is not disproved, we accept it as tentatively true. A careful scientist will test the hypothesis with different experiments or observation. If the hypothesis still stands, she feels more confident of the hypothesis.
It’s easy to create hypotheses but it takes time and effort to test them. An untested hypothesis has no scientific validity. Nevertheless, a number of untested hypotheses to explain aspects of nature are treated as being true.

A recently published paper in the journal Behavioural Ecology tested an old explanation of why many butterflies and moths have circular patterns on their wings that look like the eyes of a vertebrate. Over 150 years ago, the suggestion was made that these eyespots mimic the eyes of the predators of the enemies of the butterflies and hence offer the butterflies some protection.

That explanation is quite plausible and in fact is a commonly cited example in animal behavior texts. But until now, it had never been tested. The researchers from Cambridge University crafted artificial moths out of paper and drew different kinds of markings on the models (bars, squares, eyespots, no markings). A small mealworm was attached to each moth model to tempt Blue Tits, Great Tits and House Sparrows.

The researchers found that artificial moths with eyespots were attacked as frequently as moths with bars or squares. The scientists found that more boldly marked moths, regardless of he shape of the markings, were avoided to a greater degree than lightly marked moths. Thus, the old explanation has been tested and found wanting. Predators avoid moths and butterflies with eyespots because they are conspicuous, not because they mimic a predator’s eyes.

Let’s continue this thread with some of my own research. Over the past decade, the concept of short-stopping has been applied to irruptive birds like northern finches and Red-breasted Nuthatches. The claim is that birds like Evening Grosbeaks and Purple Finches do not migrate as far south as they did 30 years ago because of the great increase in bird feeding over those 30 years. Thus, the hypothesis goes, Purple Finches use to need to migrate to North Carolina to find food in the winter but now can take advantage of the many sunflower seeds that New Englanders put out for the birds.

Like the eyespot hypothesis above, this short-stopping hypothesis seems like a reasonable one but was offered without a scientific effort to disprove it.

In 1999, I published a paper that tested this hypothesis. Specifically, I examined the irruptions of Common Redpolls. Purple Finches, Evening Grosbeaks, Pine Siskins, White-winged Crossbills and Pine Grosbeaks from eastern North America. I also examined Downy Woodpeckers, two species that do not migrate, as controls for my methodology. I divided the period from 1970 to 1990 into five-year intervals. Using Christmas Bird Count data, I found that irruptions of Evening Grosbeaks and Purple Finches extended further south in the earlier time periods. However, if irruptive birds are staying further north in more recent years, one would expect a corresponding increase in these irruptive birds in northern areas. I did not find such a pattern of increase and therefore my analysis failed to support the short-stopping hypothesis.

[Originally published on March 8, 2008]

For the Birds - American Robin movements; Bird records

American Robins

A large influx of American Robins has occurred in Maine in the past couple of weeks. Some observers report flocks of 75 birds. The arrival of robins is often taken to be a sign of spring but don’t be fooled. These robins are almost certainly birds from the north that have been pushed south by lack of food. If you see a bunch of robins, take a close look at them. Some of them will likely have the dark back of the Newfoundland race of American Robins.

Most birds are remarkably tolerant of cold weather as long as they have sufficient food to support their increased metabolic demands in the winter. Common Redpolls can winter as in latitudes as high as 70 º N as long as they can find enough seeds. When seed production is low, they are forced to move south and we get to enjoy seeing these delightful sprites. Similarly, American Robins can tough out the winter in the Maritime Provinces and Newfoundland as long as sufficient fruit is available. When the fruit is depleted, the robins have no choice but to move south in search of food.

Owls

The heavy snowpack, and more importantly, the ice layers in the snow pack pose a huge challenge to our larger owls that depend on rodents and other small mammals for food. A number of birders have observed Barred Owls in the daytime in the past couple of months. Their daytime activity is almost surely a sign of the owls’ difficulty in finding food. The scarcity of available food makes it necessary for owls to forage both during the day and night.

At our feeding station in South China, we were treated to the presence of a Northern Saw-whet Owl. It was perching on a feeder pole, no doubt waiting for a vole or shrew to come out of snowpack to feed on some of the seeds that had fallen from the bird feeders.

Records

We certainly haven’t lacked for snow across the state this winter. Northern Aroostook County has been hit quite hard. As of this writing, Caribou has had 137 inches of snow this winter, 59 inches above normal, and is on a pace to set a new yearly snowfall record. With records on my mind, I thought a consideration of some bird records might be of interest.

The largest living bird is the Ostrich, a flightless bird that tips the scales at 345 pounds and reaches a height of nine feet. But that pride of place is unwarranted. The heaviest birds we know of were the elephant birds found in Madagascar until they went extinct around 1600. Those birds topped out at 1000 pounds. Their eggs had a two-gallon capacity and were in fact used as buckets by the Malagasy people. The tallest bird was one of 24 species of flightless moas found in New Zealand. Those were all exterminated by the year 1500. Dinornis means terrible bird, not a very fitting name for a leaf-eater.

How about the largest bird capable of power flight? That record belongs to the Great Bustard, a Eurasian grassland bird. Individuals may weigh as much as 46 pounds. However, the fossil record has even larger birds that we believe could fly under their own power. Four species of vulture-like birds called teratorns are known from North and South America, first appearing about 25 million years ago. The largest, Argentavis magnificens, had a wingspan of 26 feet. See the photograph at: http://farm2.static.flickr.com/1301/699750340_e5d88a64a1.jpg
At the other end of the spectrum, the smallest bird is the Bee Hummingbird found in Cuba. An adult weights only 1.6 grams, half the weight of a penny. Check out the picture of a Bee Hummingbird perched on a pencil eraser:
http://www.avianweb.com/images/birds/hummingbirds/bee.jpg

Humans are fascinated by speed records. For birds, the fastest speed ever measured was achieved by a Peregrine Falcon. The bird was in a stoop, making its body aerodynamically smooth and thus able to knife through the air with a minimum of friction. That diving bird was clocked at 117 mph!

It is appropriate that the speed record for flapping flight is held by a swift. The White-throated Needle-tailed Swift can achieve a speed of 107 mph. Red-breasted Mergansers are no slouches, though. These birds have been timed at 100 mph in level flight.

The birds that have the heaviest flight muscles relative to their body weight are the hummingbirds. That fact is not surprising because hummingbirds generate lots of power (upward lift and forward thrust) on the upstroke as well as the downstroke.

[Originally published on February 23, 2008]

For the Birds - Highlights of Maine Christmas Bird Counts - III

This column is the last of three reviewing the highlights of some of the National Audubon Society Christmas Bird Counts for the 2007/2008 season. The six counts covered today span the breadth of our state.

We’ll start with the Misery Township Count, held on December 30. This count in the vicinity of The Forks south of Jackman has significantly colder weather than most of the other counts in the state. The species number and bird abundance for this circle are usually quite low but the potential for boreal species is high. This year’s count yielded 18 species. Highlights were three Bald Eagles, a Northern Goshawk, two Gray Jays, 75 Pine Grosbeaks and 30 Common Redpolls.
The remoteness of this count is indicated by the fact that a single Rock Pigeon was found. Also, the five American Crows were outnumbered by the 17 Common Ravens.

The most common species was Black-capped Chickadee with 124 birds found. No Boreal Chickadees were counted this year.

The Biddeford-Kennebunkport Count, held on December 29, produced a list of 79 species. Two Wood Ducks were the most unusual waterfowl among the 15 species of ducks and geese found. Northern Gannets put on a good show with 20 birds counted. Both cormorants were found, eight Great Cormorants and a single Double-crested.

Four species of diurnal raptors were counted with an American Kestrel being the most unusual for this time of year. Thirty-five Sanderlings were found on the beaches in the count circle and 39 Purple Sandpipers were on rocky headlands.

The alcid diversity was excellent with four species tallied: two Dovekies, a Thick-billed Murre, three Razorbills and three Black Guillemots.

Barred and Great Horned owls were detected this year. A northern flavor was imparted by the seven Northern Shrikes, three Bohemian Waxwings, and 22 Snow Buntings. Eight finch species were found with the three Red Crossbills, two White-winged Crossbills and three Evening Grosbeaks being particularly notable. Lingering birds from the summer included a Winter Wren, nine Eastern Bluebirds and a Brown-headed Cowbird.

The Monhegan Island count on January 3 yielded 46 species. Highlights included a Peregrine Falcon, a Dovekie, a Northern Shrike, three Carolina Wrens, a Yellow-rumped Warbler, a Fox Sparrow, a Rusty Blackbird and five Common Grackles.

The three counters found 11 Iceland Gulls and a Glaucous Gull to go along with the four Ring-billed Gulls, 80 Herring Gulls, five Great Black-backed Gulls and 54 Black-legged Kittiwakes.

Moving downeast, the Machias-Jonesport count on December 30 resulted in a final tally of 51 species. Four species of dabbling gulls were found. The nine Northern Pintails and single Green-winged Teal were excellent finds among the expected Mallards and American Black Ducks. Sixteen species of waterfowl were found in all. A single Barrow’s Goldeneye was a nice find.

Two Double-crested Cormorants lingered and none of our usual winter species, the Great Cormorant, were noted. The only birds of prey were 13 Bald Eagles and a Sharp-shinned Hawk.

A Tufted Titmouse was a good sighting as this species continues to expand into the middle third of our state. A Yellow-shafted Flicker was awfully late for this species; most depart the state by November.

Finch abundance was modest with only four species found: 46 Pine Grosbeaks, four Common Redpolls, three Pine Siskins and a lone American Goldfinch.

The final two counts, the Orono-Old Town count (December 15) and the Bangor-Bucksport count (December 29), are interesting to compare because of their proximity. These two counts yielded 49 and 50 species, respectively.

The Penobscot River is a good place for Barrow’s Goldeneyes in Maine. Orono counters found 25 to go along with 25 Common Goldeneyes. The Bangor counters found three Buffleheads, an unusual inland sighting for the winter in Maine.

Orono had five species of birds of prey including a Rough-legged Hawk and an American Kestrel. Bangor had three hawk species.

Bangor had an excellent sighting of a Red-bellied Woodpecker. Hairy Woodpeckers were more common than Downy Woodpeckers on both counts.

Two Northern Shrikes were found in Orono and three in Bangor. Tufted Titmice showed well with 32 in Bangor and 17 in Orono. Both counts had one Northern Mockingbird.

Orono had a fine count of 638 Bohemian Waxwings but that was dwarfed by the 2,016 Bohemians found in Bangor. A Common Grackle in Orono was late.

Pine Grosbeaks were the most numerous northern finch although both counts also had Purple Finches, Common Redpolls and Evening Grosbeaks.

[Originally published on February 9, 2008]

For the Birds - Highlights of Maine Christmas Bird Counts - II

This column is the second of three reviewing the highlights of some of the National Audubon Society Christmas Bird Counts for the 2007/2008 count. We’ll examine three coastal counts in today’s column. I’ll cover them from south to north.

The Bath-Phippsburg-Georgetown Count, held on December 15, produced a list of 87 species. The number and diversity of birds associated with water were outstanding. Sixteen species of waterfowl were present. The 1,110 American Black Ducks was an impressive total. Other notable high counts were 792 Common Eiders, 160 Black Scoters, 368 Bufflehead, 28 Barrow’s Goldeneyes and 101 Hooded Mergansers.

Loons were found in good quantity: 79 Common Loons and 19 Red-throated Loons. The grebe family was represented by 49 Horned Grebes and 84 Red-necked Grebes.

Twenty Bald Eagles and 10 Red-tailed Hawks were found along with two Sharp-shinned Hawks, a Rough-legged Hawk and a Merlin.

Fifteen Dunlin and 34 Sanderlings were nice accompaniments to the 223 Purple Sandpipers. An unexpected shorebird was the singleton American Woodcock.

South of Cobscook Bay, Black-legged Kittiwakes tend to be found offshore at this time of year. With a bit of effort, kittiwakes can be seen from shore with a spotting scope. The Bath counters found 27 this year. An excellent sighting was a single Pomarine Jaeger, typically a pelagic species in Maine. In addition to the 28 Black Guillemots, six Razorbills added to the alcid diversity on this count.

Open countryside and coastal beaches attract a characteristic suite of ground-dwelling land birds. The Bath counters scored a grand slam with these species, finding 28 Horned Larks, one American Pipit, 113 Snow Buntings and one Lapland Longspur.

Lingering landbirds included a Northern Flicker, a Carolina Wren, a Hermit Thrush, a Yellow-rumped Warbler, three Red-winged Blackbirds, three Common Grackles and a Brown-headed Cowbird.

Irruptive species included six Bohemian Waxwings, 114 Pine Grosbeaks, three White-winged Crossbills and 27 Common Redpolls.

The Pemaquid-Damariscotta count, held on December 29, yielded a count of 55 species. Common Eider with 810 individuals was the most common duck found on the count. A single Harlequin Duck was a good find as was the single Barrow’s Goldeneye. A total of 97 Common Loons was tallied but no Red-throated Loons this time.

Six Bald Eagles were the only birds of prey on this winter’s count. Four species of gulls were found with the 657 Herring Gulls being the most abundant by far. The only alcids this year were six Black Guillemots and two Razorbills.

A Belted Kingfisher was a good find at this time of year. A Northern Flicker was the only other land bird that was lingering beyond the normal departure date for the species.

Irruptive species included a Northern Shrike and seven Bohemian Waxwings .

The finch diversity was outstanding with seven species counted, including 14 Pine Grosbeaks, one Purple Finch, a Common Redpoll, 12 Pine Siskins, 8 American Goldfinches and a fine count of 19 Evening Grosbeaks. A Red Crossbill was seen in the area just after the count.

The Schoodic count, held on January 3, produced a list of 46 species. Ten species of waterfowl were counted. The most abundant ducks were Common Eiders (305) and Buffleheads (309). A total of 24 Common Loons was found. Grebe numbers were modest with only 10 Horned Grebes and five Red-necked Grebes this year. Five Great Cormorants were recorded.

Only two raptors species were found this year. The raptors seen were eight Bald Eagles and two Northern Goshawks. Excellent quality if not quantity.

Purple Sandpipers, a wintering species in Maine on rocky shores, are notoriously patchy in their distribution. This year, Schoodic counters found only nine of these shorebirds.

Five species of gulls were found, highlighted by excellent counts of Iceland Gulls (six) and Glaucous Gulls (eight).

The Schoodic peninsula is dominated by coniferous forest. One would expect that Red-breasted Nuthatches, which prefer coniferous forest, would outnumber White-breasted Nuthatches, a species more associated with deciduous forest. That expectation was met with 12 red-breasts and 3 white-breasts tallied.

Tufted Titmice and Northern Cardinals have been expanding their ranges northward over the past 30 years. The downeast coast is at the frontier of this expansion. Schoodic counters found four Tufted Titmice and five Northern Cardinals.

Other notable records this year included a single Lapland Longspur and 124 Pine Grosbeaks.

[Originally published on January 26, 2008]

For the Birds - Highlights of Maine Christmas Bird Counts - I

We are in the middle of the National Audubon Society Christmas Bird Count. As usual, the next columns will discuss the results of this important winter bird census in the United States, Canada and beyond. Until then, I thought it might be fun to think about the colorful language that has been used over the years to describe species of birds in North America.

Bluebill, baldpate, log-cock, high-hole, rain crow. These are all common names for different birds that are found in Maine. The common names used in different parts of the North America are being collected by an avian etymologist, Waldo McAtee. So far McAtee has found over half a million of these common names for our 800 species of birds.

The difficulty with common names is that confusion may arise over the particular species in question. For instance, the colloquial name of log-cock for the Pileated Woodpecker could reasonably be used to describe a Ruffed Grouse.

Biologists avoid the uncertainty of common names by using the standardized scientific name which consists of a genus name and a species name. However, most birdwatchers don't care to commit lots of Latin names to memory.

Fortunately, the Checklist Committee of the American Ornithologists' Union published a list of standard common names in 1957. The checklist is periodically revised to reflect increasing knowledge of bird classification. The common names used in field guides are the standardized common names. Use of these names rather than colloquial names reduces confusion. It is also a lot easier to say you saw three Blue Jays rather than three Cyanocitta cristata!

Some common names are descriptive and easily understood. For instance, woodpecker is a highly appropriate name for those birds which probe dead wood for insects. Flycatcher is another straightforward descriptive name. Other names are more obscure but interesting in terms of their word origin. I will discuss some of the less obvious common names of North American birds in the rest of today’s column.

Cormorants are often seen along the major rivers and on larger lakes in our region. Cormorant comes from two Latin words: corvus , meaning crow and marinus, meaning marine. So, cormorant is another way of saying sea-crow. Cormorants have little in common with crows besides their black plumage but the derivation of the word is charming.

Loon is an interesting term that is thought to derive from the Shetland word loom or the Icelandic word lomr. Both words mean lame and aptly describe the awkward walking of loons on land. The feet of loons are located near the rear of the body for efficient swimming but ungainly walking.

Hooded and Common Mergansers are frequently seen on larger bodies of water in our area. Merganser comes from two Latin words: mergus, meaning diver and anser, meaning goose. A perfectly apt description of these birds. One that is less appropriate is Bufflehead, a small diving duck that often is found with mergansers. Bufflehead is supposedly derived from buffalohead. It takes a little imagination to see the similarity of the heads of Buffleheads and buffaloes!

Falcon comes from the Latin falx, meaning sickle. The powerful bill of a falcon certainly bears a functional similarity to a sickle.

Gull comes from the Latin gula, meaning throat. Just like a person who is gullible, a gull will swallow anything!

Color may be the basis of the common name of birds. The Northern Cardinal is named for the high church official who wears a bright red robe. The Northern Oriole's name comes from the Middle Latin oriolus or the Latin aureolus, meaning golden.

The Eastern Kingbird is so named because of the small patch of red feathers on the top of its head that the male exposes when it is excited. The Ruby-crowned Kinglet is a much smaller bird but males have the same type of red crown as the kingbird.

We often say that birds chirp. This trait has given rise to at least two common names. The American Pipit, a bird that breeds on Mt. Katahdin and may be found in our state in agricultural fields in the spring and fall, has a name derived from the Latin pipo, meaning to chirp. The Swedish word siska means a chirper and gives us the common name for the Pine Siskin.

Finally some common names are based on the calls or songs of birds. Good examples of this type of common name are chickadee, whip-poor-will, cuckoo, curlew and towhee. The doleful call of the Mourning Dove gives this bird its name.

[Originally published on January 12, 2008]

For the Birds - Etymologies of Common Names of Birds

We are in the middle of the National Audubon Society Christmas Bird Count. As usual, the next columns will discuss the results of this important winter bird census in the United States, Canada and beyond. Until then, I thought it might be fun to think about the colorful language that has been used over the years to describe species of birds in North America.

Bluebill, baldpate, log-cock, high-hole, rain crow. These are all common names for different birds that are found in Maine. The common names used in different parts of the North America are being collected by an avian etymologist, Waldo McAtee. So far McAtee has found over half a million of these common names for our 800 species of birds.

The difficulty with common names is that confusion may arise over the particular species in question. For instance, the colloquial name of log-cock for the Pileated Woodpecker could reasonably be used to describe a Ruffed Grouse.

Biologists avoid the uncertainty of common names by using the standardized scientific name which consists of a genus name and a species name. However, most birdwatchers don't care to commit lots of Latin names to memory.

Fortunately, the Checklist Committee of the American Ornithologists' Union published a list of standard common names in 1957. The checklist is periodically revised to reflect increasing knowledge of bird classification. The common names used in field guides are the standardized common names. Use of these names rather than colloquial names reduces confusion. It is also a lot easier to say you saw three Blue Jays rather than three Cyanocitta cristata!

Some common names are descriptive and easily understood. For instance, woodpecker is a highly appropriate name for those birds which probe dead wood for insects. Flycatcher is another straightforward descriptive name. Other names are more obscure but interesting in terms of their word origin. I will discuss some of the less obvious common names of North American birds in the rest of today’s column.

Cormorants are often seen along the major rivers and on larger lakes in our region. Cormorant comes from two Latin words: corvus , meaning crow and marinus, meaning marine. So, cormorant is another way of saying sea-crow. Cormorants have little in common with crows besides their black plumage but the derivation of the word is charming.

Loon is an interesting term that is thought to derive from the Shetland word loom or the Icelandic word lomr. Both words mean lame and aptly describe the awkward walking of loons on land. The feet of loons are located near the rear of the body for efficient swimming but ungainly walking.

Hooded and Common Mergansers are frequently seen on larger bodies of water in our area. Merganser comes from two Latin words: mergus, meaning diver and anser, meaning goose. A perfectly apt description of these birds. One that is less appropriate is Bufflehead, a small diving duck that often is found with mergansers. Bufflehead is supposedly derived from buffalohead. It takes a little imagination to see the similarity of the heads of Buffleheads and buffaloes!

Falcon comes from the Latin falx, meaning sickle. The powerful bill of a falcon certainly bears a functional similarity to a sickle.

Gull comes from the Latin gula, meaning throat. Just like a person who is gullible, a gull will swallow anything!

Color may be the basis of the common name of birds. The Northern Cardinal is named for the high church official who wears a bright red robe. The Northern Oriole's name comes from the Middle Latin oriolus or the Latin aureolus, meaning golden.

The Eastern Kingbird is so named because of the small patch of red feathers on the top of its head that the male exposes when it is excited. The Ruby-crowned Kinglet is a much smaller bird but males have the same type of red crown as the kingbird.

We often say that birds chirp. This trait has given rise to at least two common names. The American Pipit, a bird that breeds on Mt. Katahdin and may be found in our state in agricultural fields in the spring and fall, has a name derived from the Latin pipo, meaning to chirp. The Swedish word siska means a chirper and gives us the common name for the Pine Siskin.

Finally some common names are based on the calls or songs of birds. Good examples of this type of common name are chickadee, whip-poor-will, cuckoo, curlew and towhee. The doleful call of the Mourning Dove gives this bird its name.

[Originally published on December 29, 2007]

For the Birds - Cyberbirding

It has been a while since I wrote about resources for birders and ornithologists on the internet. Today’s column will cover several innovations in cyberbirding. The Cornell Laboratory of Ornithology (hereafter, CLO) figures prominently in all of these resources.

The CLO has long been a depository for sound and video recordings of birds and other animals. Now that these files can be saved in digital format, they are easily shared with researchers and interested people.

The Macaulay Library of Natural Sounds at the CLO boasts the largest collection of sound recordings of animals in the world. Some of these sound recordings have associated video. The entire collection of recordings is currently being digitized. Currently over 65,000 sound clips and 18,000 video recording are available as streaming files for free.

The sound files can be played using the free application RealPlayer. Better yet, a free tool called RavenViewer can be downloaded. This tool works within QuickTime. RavenViewer not only allows you to play the sound recordings but to visualize the recordings in real time. A wave form of the sound scrolls across the screen showing the loud and soft portions of the file. Even more useful is the spectrogram that shows the frequencies of each part of the sound.
The sound and video recordings provide a great opportunity for learning. I searched for American Robin and found that 431 recordings are in the Macaulay Library, and nearly all have been uploaded for users to hear.

The focus of the on-line recordings is on North American species, mainly birds, although many recordings made outside of North America are available. To visit the Macaulay Library, go to: http://www.animalbehaviorarchive.org/

eBird

The CLO is maintaining a nationwide digital system for sharing birding observations. After a field trip, contributors simply visit eBird at http://ebird.org/ and enter the numbers of individuals of each species of bird they saw on a field trip along with the location. These records become part of a database that can be searched by anyone. Imagine you will be on a trip to Cleveland in April and want to know what birds you might be able to see. A quick search of the eBird database will give you tons of records of birds that other birds have seen in that area in the spring.

eBird keeps track of all the records you have added to the database and will keeps a lifelist for you. You can enter data taken from trips years ago. All of those records are valuable.

The eBird software knows when you have made an unusual sighting and will prompt you to make sure that other possible identifications have been eliminated. Rare bird sightings are tagged as such and can be sent to birders who like to keep abreast of local rarities.

The easiest way to keep track of these rarities is to use the eBird gadget (http://ebird.org/content/ebird/news/Google_Gadget.html). This is a tool that you load to a personalized iGoogle page (go to http://www.google.com/ig to set up the page). The eBird gadget will search the state of your choice for recent rarities. In looking at the eBird gadget list in my iGoogle page, I see that recent rarities in Maine are Eastern Screech Owl, Orange-crowned Warbler and Black-headed Gull. Directions and a map for the location of each sighting are provided.

Birds of North America

This project was born nearly 20 years when the Academy of Natural Sciences in Philadelphia devised a way to assess the cumulative knowledge of all North American breeding birds. A specialist was found to write an account for each of the over 700 species covered. Each account is in a standard format with the same organization throughout (e.g.,, Distribution, Distinguishing Characteristics, Migration, Habitat, Sounds,). One of the most valuable aspects of each account is the extensive bibliography on each species at the end of the account.

The 720 volumes were initially issued in paper. The accounts are now in digital format as well. One advantage of the digital accounts is that they can be easily updated as new information arises. A second advantage is that users do not need twelve feet of shelf space to house the collection.

The digital version of Birds of North America is administered now through the CLO (http://bna.birds.cornell.edu/bna). A yearly subscription is only $40.

The CLO has recently made an abbreviated form of each account available for free. This resource is called All About Birds. It can be found at: http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/ You can find links on that page to basic identification skills, bird gear and attracting birds to your backyard.

[Originally published on December 15, 2007]

For the Birds - Gift Recommendations

The holiday gift season is upon us. Several people have asked me for gift recommendations for birders. I thought I might share some suggestions in today’s column.

All birders need a field guide and my favorite is the Sibley Guide to Birds. This guide covers all the birds recorded in North America and multiple illustrations are provided for most species. A downside of the Sibley Guide is its size, far too large to fit in a coat pocket for easy carrying in the field. To make a more portable guide, the Sibley Guide has been reconfigured into two smaller, pocket-size guides. One is for birds of eastern North America and one for the western part of our continent. The portable guides do not have all of the illustrations or text of the large Sibley Guide.

The Sibley Guides are not the only field guides to North American birds and I recommend that birders own several different field guides. Each will have information that others lack. The National Geographic Field Guide to the Birds of North America has just been published in its fifth edition. This guide covers all the birds of North America but is much more smaller and portable than the original Sibley Guide.

People on your gift list who are just beginning to get into birding might appreciate a copy of the Peterson Guide to the Birds of Eastern North America. Roger Tory Peterson’s arrow system, in which critical field marks are indicated on his excellent illustrations, is helpful for beginning to intermediate birders.

Peterson, who passed away in 1996, was one of the most influential figures in bird identification in the 20th century. From 1984 until his death, he wrote a bird column in the Bird Watcher’s Digest. The best of those essays have been collected in a book called All Things Reconsidered: My Birding Adventures. The essays are great fun to read and the book is a real bargain.
Bernd Heinrich’s Ravens in Winter is a scientific detective story. Heinrich, a retired biology professor at the University of Vermont, owns a large tract of property in Maine near Mount Blue State Park where he has done much research over the years. The mystery concerns a Common Raven that discovered a moose carcass. Ravens depend on carcasses for much of their nutrition during the winter and this moose was a veritable bonanza. But instead of taking advantage of the food, the raven flew widely over the woods, calling vigorously. The raven was announcing the find to other ravens. The party was on! Heinrich could not understand why the original discoverer would be willing to share. Why was this raven an altruist? Wouldn’t it be better for the discoverer to keep the location of the carcass secret?

Ravens in Winter is a recounting of the blind alleys and fruitful avenues that Heinrich took to ultimately solve the mystery. The book is a fine recounting of the way that science is conducted.

Ravens are considered some of the most intelligent birds. In a subsequent book, Mind of the Raven, Heinrich explores the behavior of Common Ravens in Maine and beyond. He recounts many of his own experiments and observations, supplemented by summaries of the work of other raven researchers. The reader comes away with great appreciation for the intelligence of the “wolf-bird”.

For people who want an authoritative treatment of the field of ornithology, Ornithology by Frank Gill and Handbook of Bird Biology, written by a number of ornithologists at the Cornell Laboratory of Ornithology, will fit the bill. The Handbook comes with a CD of bird vocalizations, discussed in the book.

I have four recommendations for DVD’s. Each is beautifully filmed and heart-warming in its own way. March of the Penguins describes the incredibly arduous reproduction of Emperor Penguins in Antarctica. The film clearly depicts the remarkable adaptations these penguins have to allow them to survive and reproduce in the deep Antarctic cold.

Winged Migration is a visual delight with a minimum of narration. Using ultralight aircraft, the videographers filmed cranes, geese and other birds in flight. Footage comes from a number of locations, from Antarctica to New York City to equatorial South America.

The Wild Parrots of Telegraph Hill is a documentary of the relationship between Mark Bittner, a homeless musician in San Francisco, and a flock of released parrots. You will come to know many of the parrots. It is a love story in more ways than one.

Finally, consider giving David Attenborough’s Life of Birds DVD collection to a birding friend or family member. This set has ten hours of superb footage of all aspects of the biology of birds. Don’t miss the footage of the Superb Lyrebird that mimics a camera shutter and a chain saw!

[Originally published on December 1, 2007]