Bay-breasted Warbler

Tiny, threadlike notes rock between two pitches in a steady seesaw pattern. The sound is delicate enough to disappear into canopy noise.

A long-distance migrant. Breeds from much of boreal Canada south locally into the northeastern United States, including northern New England and the Great Lakes region. Winters mainly in northern South America, especially around the Andes foothills and adjacent lowlands, with smaller numbers in Central America and the Caribbean.

Breeds mainly in mature boreal coniferous and mixed forests, especially spruce and fir, often where spruce budworm outbreaks provide abundant food. During migration it uses a wide range of wooded habitats including deciduous forests, forest edges, parks, and shelterbelts. It winters primarily in tropical forests, woodland edges, and shaded coffee plantations in northern South America and parts of Central America.

Most noticeable in spring and fall migration, when it passes through the eastern half of North America. It breeds from late spring into summer in northern conifer forests. Fall birds are often overlooked because nonbreeding plumage is subdued and easily confused with other warblers, especially Blackpoll Warbler.

A small, compact wood-warbler of the boreal forest, the Bay-breasted Warbler is most striking in breeding plumage, when males show a rich chestnut throat, flanks, and crown patch set against a dark face and creamy buff neck. Outside the breeding season it becomes much duller—olive above with buffy underparts—making it one of the trickier fall warblers to identify. It is best known as a migrant through eastern and central North America and as a spruce-fir breeder in Canada and the northeastern United States.