Wilson's warbler
Template:Short description Template:Speciesbox Wilson's warbler (Cardellina pusilla) is a small New World warbler. It is greenish above and yellow below, with rounded wings and a long, slim tail. The male has a black crown patch; depending on the subspecies, that mark is reduced or absent in the female. It breeds across Canada and south through the western United States, and winters from Mexico south through much of Central America. It is a very rare vagrant to western Europe.
TaxonomyEdit
Wilson's warbler was formally described in 1811 by the ornithologist Alexander Wilson under the binomial name Muscicapa pusilla.<ref>Template:Cite book</ref> The type locality is southern New Jersey.<ref>Template:Cite book</ref> The species was moved to the genus Wilsonia by the naturalist and ornithologist Charles Lucien Bonaparte in 1838. Zoologist Thomas Nuttall moved it to Sylvania in 1840, and by 1845, many authors included it in Myiodioctes. In 1899, the American Ornithological Union returned the species to Wilsonia.<ref>Template:Cite book</ref> The species is currently assigned to the genus Cardellina.<ref>Template:Cite journal</ref> The genus name Cardellina is a diminutive of the Italian dialect Cardella, a name for the European goldfinch, and the specific epithet pusilla means "very small".<ref name =job>Template:Cite book</ref>
There are three recognized subspecies:<ref name=ioc>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
- C. p. pusilla was described by Alexander Wilson in 1811.<ref name="ITIS">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- C. p. pileolata was described by German naturalist Peter Simon Pallas in 1811.<ref name="ITIS"/>
- C. p. chryseola was described by Robert Ridgway in 1902.<ref name="ITIS"/>
The chryseola subspecies, which nests in northern coastal California to southwestern coastal Canada, has a distinctive orange-tinged yellow forehead. The population of the subspecies has declined sharply in the 21st century because it migrates preferentially to the southern end of the Baja Peninsula in Mexico,<ref>Template:Cite journal</ref> where luxury resort and residential developments have replaced the bird's habitat.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
DescriptionEdit
.jpg){kind=link}
Wilson's warbler is a small passerine, ranging from Template:Convert in length, with a wingspan of Template:Convert and a mass of Template:Convert.<ref name=CornellID>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It has a plain green-brown back and yellow underparts. The male has a small black cap. Males of the western race C. p. chryseola are greener above and brighter than males of the eastern, nominate race. Individuals from Alaska and the west-central portion of the species' range average slightly larger than those found in eastern and Pacific coastal populations.<ref name=CornellID/> Its song is a chattering series of loud descending notes. The call is a flat "chuff".<ref name="Boreal birds"/>
Wilson's warbler resembles the yellow warbler: the latter is readily distinguished by its different shape, yellow wing markings, and yellow tail spots.<ref>Template:Cite book</ref>
Distribution and habitatEdit
The breeding habitat is fairly open woodland with undergrowth or shrubs and thickets in moist areas with streams, ponds, bogs, and wet clearings.<ref name="Boreal birds">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Wilson's warbler breeds in northern Canada and the western US; it winters in overgrown clearings and coffee plantations,<ref name="Boreal birds"/> forest edges, deciduous forests, tropical evergreens, pine-oak forests, mangroves, thorn-scrub, riparian gallery forests, brushy fields, and mixed forests . At all seasons, it prefers secondary growth, riparian habitats, lakes, montane and boreal forests with overgrown clearcuts. It is a very rare vagrant to Western Europe.<ref name=CornellID/>
Behavior and ecologyEdit
BreedingEdit
Nesting generally begins in early March in west coast populations, and extends into August in the northern range.<ref name="Boreal birds"/> The female does the majority of the nest building. The cup nest is typically constructed of vegetation and lined with grasses and hair. It is often sunken into moss or sedges at the base of shrubs.<ref name="Boreal birds"/> The clutch varies from 2 to 7 eggs, which are creamy or off-white with fine reddish spots. The young are altricial.<ref name=CornellID/> The montane populations generally have a higher clutch size and nest success rate than those on the coast.<ref name="Boreal birds"/> The eggs hatch at 11–15 days and the young fledge at 8–13 days; adults care for them for several weeks. Some montane populations are polygamous (one male breeds with multiple females).<ref name="Boreal birds"/> Wilson's warbler is a frequent host for the brown-headed cowbird.<ref name="Boreal birds"/>
FeedingEdit
Wilson's warbler is an insectivore, feeding primarily on insects gleaned from leaves and twigs, or caught by flycatching.<ref name=Curson>Template:Cite book</ref> Some of these insects include beetles, bees, or caterpillars. Wilson's warbler is an active forager, moving rapidly through shrubs, on the ground, and sometimes in taller trees during the winter.<ref name="Boreal birds"/> Feeding birds often twitch their tails or flick their wings nervously.<ref name="Benedict">Benedict, Audrey DeLella (2008). The Naturalist's Guide to the Southern Rockies. pp. 431. Template:ISBN</ref> The observed feeding rate of the male Wilson's warbler was not significantly different between males with or without mates.<ref name="Gowaty">Gowaty, P.A. (1996). Field studies of parental care in birds: New data focus questions on variation among females. Advance in the Study of Behavior, 25. 477–531.</ref> It also eats a few berries.<ref name=CornellID/>
ReferencesEdit
External linksEdit
Template:Sister project Template:Sister project
- Xeno-canto: audio recordings of Wilson's warbler
- Template:InternetBirdCollection
- Template:VIREO
- Wilson's warbler Species Account – Cornell Lab of Ornithology
- Wilson's warbler - Wilsonia pusilla - USGS Patuxent Bird Identification InfoCenter