A Delicate Song Announces Spring:
04-11-2007 - Our friends at the Vermont Institute of Natural Science (VINS) have allowed the following extract from their extremely interesting bird blog
The delicate, tinkling song of the brown creeper announces spring?s coming in Vermont?s woodlands. During the late winter doldrums of February and early March, lengthening days and warming sun incite males of this hardy species to issue their high-pitched, sprightly song. Brown creepers are among North America?s most inconspicuous songbirds, as they spiral upward on tree trunks, well-hidden by their cryptic plumage. Their thin, high tsee call can be very difficult to locate, and it is typically their tree-creeping habitat that reveals them to the patient observer. The species? slender, decurved bill is well-adapted to glean invertebrates ? mainly insects and spiders ? from bark crevices, while its long, stiff tail acts as a prop against the trunk, much as a woodpecker?s.
Although generally considered a year-round resident in Vermont and elsewhere, brown creepers are partial migrants, as individuals from northern populations often migrate south of the breeding range. One of three closely-related and very similar treecreeper species wordwide, brown creeper is the only North American representative. The northern extent of its summer range extends from Newfoundland west across the coniferous forests of Canada to southeastern Alaska. Southern nesting limits reach Maryland and Virginia in the east, while western populations extend southward through Mexico as far as Nicaragua. Eastern populations winter south to the Gulf Coast, from Florida to Mexico. Brown creepers often join mixed-species foraging flocks in Vermont during winter, most commonly in mixed or hardwood-dominated forests. During summer, the species is territorial.
Brown creepers employ a unique habit of building hammock-like nests behind a peeling or loosened flap of bark on a large dead or dying tree. The nest base is constructed of twigs and bark strips layered together, adhered to the bark?s rough inner surface with insect cocoons and spider egg cases. The inner cup is lined with fine materials such as hair, grass, leaf fragments, lichens, and feathers. Nests are extremely difficult to find, their presence usually revealed only by the comings and goings of adults, both of which feed young. Despite their welcome early singing behavior, brown creepers typically commence nesting in May or early June.
Chris Rimmer (VINS Biologist)
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