Male. Note: lack of eye arcs, gray hood, dark breast band, and pale pink bill.
  • Male. Note: lack of eye arcs, gray hood, dark breast band, and pale pink bill.
  • Juvenile. Note: thin broken eye ring and yellowish throat.

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Mourning Warbler

Oporornis philadelphia
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

    Mourning Warbler is the eastern counterpart of MacGillivray’s Warbler. The two look almost identical and the songs are also very similar. Both have olive backs, gray hoods (the lower edge is black in the adult male), and the remainder of the underparts bright yellow. The main difference is MacGillivray’s white crescents above and below the eye, present in all plumages. Mourning has a much weaker broken eye-ring in some plumages, but this is absent in most adult males. Separating these two species in the field, especially in fall, is a perilous exercise. Even experts frequently cannot agree. For this reason state bird records committees in the West reject more reports of Mourning Warbler than they accept. So far only one record has passed scrutiny from the Washington Bird Records Committee: a female seen on 26 May 2001 at Lyons Ferry Park (Franklin County); six other reports have been turned down. Mourning Warbler breeds in northeastern British Columbia and is considered to be a casual visitor elsewhere in the province. Oregon’s committee has accepted five records. There are none for Idaho.

    Mourning Warbler nests across the boreal forest belt of Canada from southeast Yukon to Labrador, south to the Great Lakes states and New England and down the Appalachians to West Virginia; winters from Nicaragua to Ecuador; and migrates through Mexico rather than overflying the Gulf.

    Revised November 2007

    North American Range Map

    North America map legend

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