Palm Warbler, watercolor on 300lb paper. The Palm Warbler (*Setophaga palmarum*) is a small, energetic songbird of the New World warbler family, measuring about 4.5–5 inches in length. It is best recognized by its habit of constantly bobbing its tail up and down — a behavior that makes it easy to identify even at a distance. During breeding season, adults display a rich chestnut cap, a bright yellow supercilium (eyebrow stripe), and yellow underparts streaked with reddish-brown, while the western subspecies tends to be duller, with more whitish underparts. The rump and undertail coverts are notably yellow year-round, which is a helpful field mark in all plumages and seasons. Palm Warblers breed in boggy, open spruce and tamarack forests across Canada and the northeastern United States, then winter in the southeastern U.S., the Caribbean, and Central America, where they are commonly seen foraging low to the ground or on open ground for insects, berries, and seeds — hence their preference for scrubby, open habitats rather than dense forest canopy despite the tropical-sounding name.