The Yellow Warbler, Dendroica petechia, is a New World warbler. It is the most widespread Dendroica warbler, breeding in almost the whole of North America and down to northern South America. It has 35 geographical races, which can be divided into three main groups.
Length is 4 inches. It is a small, active, insect-eating bird. The yellow warbler has a thin, pointed bill, mostly yellow plumage. Its upperparts greenish-yellow
Greenish-yellow wings and tail with yellow feather edges. It has a plain yellow face with yellow eye ring surrounding dark eye and yellowish legs. The adult male yellow warbler has golden yellow plumage with rusty streaks on breast and flanks. Female and immature yellow warblers have plain yellow plumage, their streaks on breast absent or barely noticeable.
Yellow Warblers nest in trees, building a cup nest. Aestiva lays 3-6 eggs, but the two other groups, which breed in mangroves, lay fewer eggs, as would be expected for tropical races.
These birds feed on insects and spiders, but northern races will also take some berries.
The yellow warbler song is a musical sweet sweet sweet, I’m so sweet, although it varies considerably between races. The call is a soft or harder ship.
This species is a regular victim of the Brown-headed Cowbird, a nest parasite.
Yellow warbler Dendroica petechia – USGS Patuxent Bird Identification InfoCenter