Male. Note: blue above and white belly.
  • Male. Note: blue above and white belly.
  • Female. Note: white spot in primaries and curved white supercilium.

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Black-throated Blue Warbler

Dendroica caerulescens
Members of this diverse group make up more than half of the bird species worldwide. Most are small. However their brains are relatively large and their learning abilities are greater than those of most other birds. Passerine birds are divided into two suborders, the suboscines and the oscines. Oscines are capable of more complex song, and are considered the true songbirds. In Washington, the tyrant flycatchers are the only suboscines; the remaining 27 families are oscines.
This large group of small, brightly colored songbirds is a favorite of many birdwatchers. Wood-warblers, usually called “warblers” for short by Americans, are strictly a New World family. Most of the North American members of this group are migratory, returning in the winter to the tropics where the family originated. Warblers that nest in the understory tend to have pink legs and feet, while those that inhabit the treetops usually have black legs and feet. North American males are typically brightly colored, many with patches of yellow. Most North American warblers do not molt into a drab fall/winter plumage; the challenge posed to those trying to identify warblers in the fall results from looking at mostly juvenile birds. Their songs are generally dry, unmusical, often complex whistles (“warbles”). Warblers that live high in the treetops generally have higher-pitched songs than those that live in the understory. Warblers eat insects gleaned from foliage or captured in the air. Many supplement their insect diet with some seeds and fruit, primarily in fall and winter, and some also eat nectar. Most are monogamous. The female usually builds the nest and incubates four to five eggs for up to two weeks. Both members of the pair feed the young.

    General Description

    Nesting in deciduous forest from western Ontario across the northern Great Lakes to the Maritime provinces, New England, and south along the Appalachians, the Black-throated Blue Warbler winters primarily in the West Indies. The adult male is unmistakable, with blue crown and back, white underparts, black face, throat, and flanks, and prominent white patch at the base of the primaries visible on the folded wing as well as in flight. Although much plainer the adult female is no less distinctive: overall grayish-brown, white eyebrow, gray cheek, and small white primary patch. Immatures resemble adult females but often show no white in the wing.

    This is one of the more regular vagrant warblers in the West. It occurs annually in California and Oregon, mostly in fall, and is no longer on the review lists of those states. Idaho has about a dozen records, the great bulk of them in September and early October. British Columbia’s six records are all from the southern part of the province—again, mostly in fall. Washington has eight accepted records, five from the Westside and three east of the Cascades. Seven of these first appeared between late September and early December; the eighth was recorded in Olympia (Thurston County) in early March. One bird remained for the entire winter at a feeder in Mercer Island (King County), from 2 November 1994 to 5 April 1995.

    Revised November 2007

    North American Range Map

    North America map legend

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