Vermont Weekly Bird Notes 1/24/2007

Many Vermont birders and feeder-watchers have reached for their field guides recently at the sight of a zebra-patterned, red-capped, medium-sized woodpecker. Some have questioned their initial identification. Red-bellied woodpecker?? That’s a southern bird! True enough, the red-bellied woodpecker (misnamed, as it has just a small wash of red on the underparts) is a characteristic bird of mature hardwoods and mixed pine-hardwoods forests of the southeastern U.S. It was virtually unheard of in Vermont prior to the mid-1990s, treated as a rarity and cause for great excitement among birders. With reports coming in weekly from feeders all over the state, it appears now to be firmly established, although still relatively uncommon, here. What’s going on?

The red-bellied woodpecker is one of the most dramatic examples of a North American species that has expanded its range northward in the past decade. Twenty-five years ago, during Vermont’s first Breeding Bird Atlas, the species went undetected over the project’s five years. During Vermont’s current second generation Atlas, coordinated by VINS (see http://www.uvm.edu/~vbba/ for more information or to participate), red-bellied woodpeckers have been recorded on 15 10x10 kilometer “blocks” during just the first 3 years, and several cases of nesting have been confirmed.

Is the red-bellied woodpecker a harbinger of a warming climate, or are there other factors that account for its rapid expansion into Vermont? The likely explanation involves a combination of factors. Yes, our less severe winters and associated subtle changes in habitat may play a role. Conventional wisdom has it that the increasing maturation of forests in the Northeast and a general increase in backyard feeders are providing conditions that favor the species’ year-round survival here. Like most woodpeckers, red-bellieds are non-migratory for the most part, and feeding stations offer a reliable food source throughout the long northern winter.

This woodpecker is an active and highly vocal species, uttering distinctive calls that aid in its identification: both loud, raspy kwirr or churr calls and shorter cha notes. Its feeding habits are catholic. Red-bellied woodpeckers seldom excavate wood for insects; instead, they forage opportunistically for a wide range of fruit, mast, seeds and arboreal arthropods. Food is occasionally stored in cracks and crevices of trees, even in fence posts. Red-bellieds are also known to take small or young vertebrate prey. The species’ generalized foraging habits have likely aided in its range expansion. Red-bellieds do well in both urban and wilderness settings, so feeder watchers anywhere in Vermont should be on the lookout for this northward-expanding bird.

Other Bird Reports

In addition to numerous red-bellied woodpecker reports, the three-toed woodpecker at Moose Bog in Ferdinand continues to reliably delight observers. Other avian highlights of the past week include a harlequin duck off Shelburne Point, single short-eared owls on both Addison and Grand Isle, a northern shrike in Waitsfield, a lingering yellow-rumped warbler in Woodstock, an eastern towhee at a feeder near Stratton Mountain, and a fox sparrow in West Brattleboro. Surprisingly early (or late) was a male red-winged blackbird at a Charlotte feeder on the 16^th, followed by a common grackle in South Burlington on the 20th. While these birds could be “winter hardies”, taking advantage of the unseasonably warm weather to linger further north than usual, one has to wonder whether we will see more and more early-arriving spring birds in years to come.

You can explore all the birds reported last week in Vermont and add your own sightings at Vermont eBird.

Chris Rimmer

Vermont Weekly Bird Notes 1/19/2007

In 1940 pet dealers on Long Island, New York, were illegally selling “Hollywood finches” when they learned that the authorities were cracking down. So they opened the cages and let the evidence fly away. Four years later the first eastern house finch nest was discovered, and during the next 20 years small breeding colonies spread outward. The population grew exponentially, expanding its range across the eastern portion of the continent.

“Hollywood finches” are actually called house finches, a western songbird closely related to our native purple finch.

In 1968 Vermont's first documented house finch sighting occurred in Marlboro. The species debuted on a Vermont Christmas Bird Count in 1974 when two individuals were found on the Ferrisburg count. The first breeding record for the species occurred the following year in 1975 when a pair brought three young to a Bennington feeder.

In 1981, the Vermont Institute of Natural Science (VINS) started a fall migration bird banding station. Two years later, the first nine finches flew into the VINS mist nets. During 1991, 410 house finches were captured, far outnumbering any other species and accounting for 15 percent of the station's total captures that fall. By 1998 the population had crashed with only 13 birds captured. So what happened?

House finches began showing up at feeders in Washington D.C. with symptoms of an eye disease in 1994. It was soon determined to be Mycoplasmal conjunctivitis, a parasitic bacterium previously known to infect only poultry. The disease produces symptoms similar to what would be observed in humans - swelling of the mucous membrane around the eye and a crusty build-up of puss, which together impair vision.

By November of 1994 the outbreak had been reported in eleven states, from New Hampshire to North Carolina, and had spread from the house finch to the American goldfinch. This explosive radiation of conjunctivitis can be attributed, at least in part, to the gregarious nature of finches. Unlike chickadees and nuthatches for instance, finches will flock to feeders in groups and feed for relatively long stretches before flying away, increasing their chances of contracting or transmitting diseases.

It is important to clean your feeders about once every two weeks. For best results wash your feeder thoroughly in soapy water, then soak or rinse it in a solution of one part bleach to nine parts water, and dry thoroughly before refilling.

Other Bird Sightings

Open lakes from the unusually warm winter has allowed for continued sightings of waterbirds last week. Common loons were observed on Lake Champlain, a double-crested cormorant and great blue heron on Lake Bomoseen, a northern pintail in Shelburne, a ring-necked duck at the mouth of the West River in Brattleboro and two white-winged scoters in a cove south of Red Rocks Park in South Burlington.

Winter raptors abound in the Champlain Valley with an observer reporting 17 northern harriers, 12 red-tailed hawks, and many rough-legged hawks. An American kestrel was found at Dead Creek Wildlife Management Area.

A red-bellied woodpecker was at a suet feeder in Sunderland. There were continued sightings of three-toed and black-backed woodpeckers at Moose Bog.

You can explore all the birds reported last week in Vermont and add your own sightings at Vermont eBird.

Kent McFarland

Arctic Visitor Soars Over Fields

Birdwatching in the expansive open fields of the Champlain Valley in winter provides a great opportunity to observe several visitors from the arctic—from Snow Buntings and Lapland Longspurs, to Snowy Owls and Northern Shrikes. One of the most consistent and most easily observed arctic breeders to winter in the valley however, is the Rough-legged Hawk. This Red-tailed Hawk-sized buteo, which frequently hovers and hunts from the wing, has small feet, a small bill, and distinctly fluffy plumage, all adaptations to arctic life. The Rough-legged gets its name from its heavily feathered legs, which, along with the Ferruginous Hawk and the Golden Eagle, are the only American hawks to have legs feathered all the way to the toes.

The Rough-legged nests on cliffs across the arctic tundra and taiga regions of the far north, feeding primarily on small mammals and some birds. In winter, it shares the same open habitats frequented by Red-tailed Hawks, but competition between the two species may be reduced by subtle differences in habitat preferences. Although there is considerable overlap, Red-tailed Hawks show a greater preference for hunting in wetter areas, and perching in trees along woodlot borders, while Rough-legged Hawks are more likely to perch in single trees, on powerline poles, or fence posts located in the open. Rough-legged Hawks also hover and hunt from the wing more frequently and effectively than Red-tails, which may facilitate foraging in large open areas less accessible to other species that require perches to hunt.

Rough-legged Hawks exhibits a high degree of plumage variation, from extremely dark individuals to more patterned birds often termed “light morphs.” Light morphs tend to outnumber dark individuals, and although the sex of most adults can be determined from plumage characteristics, intermediates occur and the variations are complex. In all plumages however, distinguishing Rough-leggeds from Red-tails is usually straight forward. Rough-leggeds have a wide, dark, terminal band on their tail. On light morph individuals, the undersides of their wings are very pale with dark carpal (or wrist) patches and a wide, dark belly band.

Recent sightings of Rough-legged Hawks include 17 individuals counted during the Middlebury Christmas Bird Count on December 26th, and 2 light morphs observed on January 7th -- one in Whiting and another observed hunting over farm fields in Orwell. Other noteworthy sightings this week include the second observation in a month of a rare Three-toed Woodpecker at Moose Bog on January 7th, a Hermit Thrush in Burlington on the 6th, and an Eastern Phoebe in Brattleboro on January 9th.

You can explore all the birds reported last week in Vermont and add your own sightings at www.ebird.org/vins.

Steve Faccio
VINS Conservation Biologist

A Dusk Spectacle

One lucky birder had an unforgettable dusk experience at the Dead Creek goose viewing area on New Year's Eve, as two Short-eared Owls put on a show. The birds were observed coursing low over the fields, uttering their nasal bark-like calls as they foraged. Dead Creek is Vermont's most reliable area to find this medium-sized, pale brownish owl of open country, and winter is the best time to seek out the species. The status of Short-eared Owls in Vermont is not well-known, although they may at least occasionally nest in the Champlain Valley. However, they are decidedly rare anywhere in the state, and it is always a treat to encounter one of these birds.

The most aerial of North American owls, Short-eareds are characterized by their long, narrow wings and bouncy, buoyant flight. They resemble Northern Harriers as they "quarter" low over open fields, often in daylight and especially at dusk during winter. Their primary prey species are small mammals such as Microtus voles, which fluctuate in abundance. Correspondingly, Short-eared Owls show considerable local variation in numbers and breeding success, even becoming nomadic at times. One of the world's most widely distributed owls, the species inhabits North America, South America, Eurasia, and many oceanic islands, including the Hawaiian chain and the Galapagos.

A ground-nesting species, Short-eared Owls have declined throughout much of their North American range, especially in the Northeast. Loss of habitat from human encroachment appears to be the primary culprit, but the species is also vulnerable to mammalian predators, especially those that prey on eggs and nestlings. The sight of Short-eared Owls bouncing like giant moths over the Dead Creek fields is a sight to remember, and one that has become increasingly less common in Vermont and elsewhere. Birders should make a special attempt to witness this spectacle over the next month or two.

Other sightings

The 18 Christmas Bird Counts (CBCs) scattered across Vermont produced a number of noteworthy sightings during the past week. Very unusual for late December were two Turkey Vultures over Bellows Falls on Dec. 26 Even more surprising was a lingering Eastern Phoebe in the Champlain Islands on Dec. 17. The Saxtons River CBC on Dec. 16 boasted several outstanding finds, including eight Carolina Wrens, four Winter Wrens, a Ruby-crowned Kinglet, an astonishing 46 Eastern Bluebirds, a single Hermit Thrush, 57 American Pipits, and one Yellow-rumped Warbler. Winter finches continue to be spotty statewide. White-winged Crossbills and Pine Siskins were found at two sites in the Nulhegan Basin east of Island Pond, while small flocks of Common Redpolls were observed in Norwich on Dec. 27 and on the Woodstock CBC on Dec. 28.

You can explore all the birds reported last week in Vermont and add your own sightings at www.ebird.org/vins.

Chris Rimmer