Cape May Warbler

The Cape May Warbler breeds in boreal spruce forest across Canada and the northern United States, with populations closely tracking outbreaks of spruce budworm as a key food source. Breeding males show a distinctive chestnut cheek patch against a yellow face and heavily streaked yellow underparts. It winters largely in the Caribbean, where it can be seen feeding on nectar in flowering trees.

Breeding male face feathers show a bright chestnut patch on the cheek, bordered by a yellow forehead and collar, with dark streaking across yellow underparts. The back is olive with dark streaking, and the rump is yellow-green. Females and nonbreeding birds are considerably duller, with a grayer face lacking strong chestnut coloring and finer streaking below, but the yellowish rump patch and streaked underparts remain useful identification features across plumages.

Breeding males show the most vivid chestnut cheek patch and boldest yellow streaking. Females and immatures are much plainer, with muted facial patterning and reduced yellow tones, sometimes appearing quite gray overall. A single complete molt occurs on the breeding grounds.

This species breeds in coniferous forest, particularly spruce stands, across the Canadian boreal region and adjacent northern United States, with local abundance fluctuating alongside spruce budworm populations. It winters mainly in the Caribbean, especially in the Greater Antilles.

Cape May Warblers have a distinctive thin, slightly downcurved bill adapted for feeding on nectar and fruit juice, particularly on the wintering grounds, in addition to gleaning insects during the breeding season. The male's song is a very high, thin, repeated note. Nests are built high in dense spruce trees. Populations can rise and fall dramatically with the boom-and-bust cycle of spruce budworm outbreaks.