The Kentucky warbler (Geothlypis formosa) is a small species of New World warbler. It is a sluggish and heavy warbler with a short tail, preferring to spend most of its time on or near the ground, except when singing.
Adult Kentucky warblers are mostly an olive-green in color on their back and nape, and a brilliant yellow below from their throat to their belly. They have a small tinge of black on their crown, and a large black mask with a yellow pattern that runs from the beak and encircles the eyes, resembling a pair of spectacles. Female Kentucky warblers have slightly less black on the sides of their head, and immature birds may have almost no black at all.