Vancouver Avian Research Centre

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Species: Townsend’s Warbler Dendroica townsendi

Description:

A colourful, distinctive wood-warbler that breeds among the treetops of mature fir forests in the Pacific Northwest, Townsend’s Warbler also nests in montane spruce-fir forests in Idaho, Montana, and northwest Wyoming, and boreal forests in Alaska and the Yukon Territory. In September, it begins its southward migration to California and the highlands of Mexico and Central America, where it is the most common of all species (including residents) in some locales.
The Townsend’s Warbler is unique within the complex of closely related ‘virens’ warblers in having extensive yellow on the breast and a dark cheek patch; the back is green in all plumages. Hybridization with the Hermit Warbler is frequent where the breeding ranges overlap, primarily in Washington State.

Identification:

General: Medium-sized, rather long-tailed warbler with rather small bill. Total length about 12 cm; body mass about 9g.

Adult Male: Bright yellow stripes bordering black cheek-patch. Crown and throat black; yellow extends below throat to lower breast; remaining underparts white; sides and flanks streaked black. Back olive green, with distinct black streaks or spots. Two white wing-bars and extensive white in outer tail-feathers.

Adult female: Differs from male in that female has generally duller markings and colouration, crown is olive green with thin black streaks, cheek-patch is deep olive (not black), throat is yellow and has variable amount of black markings, and back has less distinct black streaks than male.

Juvenile: Similar to adult female, but back has indistinct streaking; throat and breast yellow; sides indistinctly streaked with dusky; tail-feather more pointed.

Similar Species: Adult male not easily confused with other western warblers. Adult female and immature resemble Black-throated Green Warbler, but Townsend’s has distinct cheek-patch and lacks yellow wash on vent. Black-throated Green has yellow face, with less contrasting dusky olive auricular markings; brighter, unmarked green back; and yellow wash on vent. Hermit Warbler lacks yellow on breast and lacks distinct cheek-patch, and streaking on underparts is indistinct and restricted to sides, if present.

Behavior: Foraging birds on the breeding grounds spend most of their time high in the crowns of tall conifers and are thus often difficult to observe. In migration and winter, foraging takes place at all levels, even near the ground, and in a broader variety of trees. During those seasons they often join mixed flocks of kinglets, chickadees and other warblers.

Habitat: Shady moist coniferous forests, where it spends much of its time high in the trees foraging for weevils, leafhoppers, scale insects, and caterpillars.

Information:

Townsend’s Warbler was among the many species first collected by John Kirk Townsend during his expedition with Thomas Nuttall through the Rocky Mountains to the Pacific Coast in 1834.
With the exception of recent studies of winter species interactions and breeding biology, most information of the life history of the Townsend’s Warbler is anecdotal or consists of isolated observations.
Nests are built high in conifers, exceptionally as low as 8ft. and as high as 100ft.
The nest is a bulky but shallow cup of plant fibers and bark, lined with moss, plant downs and hairs; the nest is placed on al limb well out from the trunk and usually protected above by a spray of needles. 3-5 white eggs wreathed and speckled with brownish markings.

Conservation Status:

No clear trends are evident although a slight overall increase is indicated from BBS. Townsend’s is possibly susceptible to forest fragmentation, as it is consistently most abundant in breeding season in extensive old growth.
 
Capture Rates


Townsend's Warbler preferred habitat is open coniferous or mixed coniferous-deciduous forests and breed slightly more north than southern British Columbia. They are therefore not seen in high numbers around our banding station. Capture rates (2010-2012; standardized as birds captured per 100 net hours) begin in August and continue through October reflecting capture of a few individuals passing through during fall migration to their southern wintering grounds.


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