Friday, May 11, 2007

Vermont Weekly Bird Notes 5/11/07

It may be called a palm warbler, but it breeds where no palm tree would dare grow, the bogs and fens in the boreal forests of Canada and the northern United States. So how did it get its name? Palm describes its winter home nicely. It was discovered by an ornithologist on part of its wintering grounds in Haiti.

Palm warblers have been migrating through on their way northward over the past several weeks. The rusty-capped palm warbler is easily recognized by the tail-wagging habit that shows off its yellow undertail. But some birders have spied something different about some of them this spring.

The palm warbler has two different forms easily identified while birding. Those that breed in the western part of the breeding range are duller, and have whitish bellies. Those breeding in the eastern part of the range are entirely yellow underneath. The two forms inhabit separate breeding grounds but share some of the same wintering grounds. The western nests roughly west of Ottawa and winters along the southeastern coast of the United States and in the West Indies while the yellow palm warbler nests east of Ottawa and winters primarily along the Gulf Coast.

Yellow palm warbler migrates slightly earlier than the western during spring and slightly later in the fall. Previous studies have found that few western palm warblers migrate through New England in the spring, instead traveling up the Mississippi valley. It is considered a rare migrant east of the Appalachians. But several Vermont birders this spring have noted otherwise.
Several weeks ago Hector Galbraith from Dummerston found 18 palms along the Connecticut River in the Hinsdale, NH area, but only 1% were western. But this week Taj Schottland from Putney noted good numbers of palm warblers at Herrick’s Cove in Rockingham. Of the 25 he observed, nearly 40% were western.

Have migration patterns changed? Was this just a one time anomaly? We don’t know, but sharp observations by birders combined with a data collecting tool like Vermont eBird can help unravel mysteries like these.

Rare bird highlights this past week had a European flavor. A black-tailed godwit, a first for Vermont, was discovered in West Salisbury by some Mad River birders. And four Eurasian widgeons were found in Ferrisburg.

New migrants are arriving daily with warm south winds. Ruby-throated hummingbirds began to show at feeders across the state on May 5. Several flycatcher species made their first appearance: yellow-bellied flycatcher at Hyde Park on May 6, least flycatcher returned to Hartland, Norwich and Middlebury on May 5, and great crested flycatcher at Dead Creek on May 6.

First sightings of warblers included: black-throated blue warbler on May 1, Nashville warbler on May 4, ovenbird, northern parula, American redstart, common yellowthroat, blackburnian, and prairie warblers on May 5.

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

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