The Palm Warbler (Setophaga palmarum) is a small songbird of the New World warbler family. The Western Palm Warbler The species comprises two distinct subspecies that may merit specific status. "Yellow palm warbler" or "eastern palm warbler" (S. p. hypochrysea) of the eastern third of the breeding range has brownish-olive upper parts and thoroughly yellow underparts with bold rufous breast and flank streaking. It migrates later in the fall than its western counterpart.
"Brown palm warbler" or "western palm warbler" (S. p. palmarum) inhabits the remaining western two-thirds of the breeding range. It has much less yellow below, with less colorful streaking, and cold grayish-brown upper parts.
Palm warblers forage on the ground much more than other warblers, sometimes flying to catch insects. These birds mainly eat insects and berries. Their constant tail bobbing is an identifying characteristic. Kirtland's, prairie, and palm warblers are the only Setophaga species that incessantly bob their tails. The song of this bird is a monotonous buzzy trill. The call is a sharp chek.
The range of the Palm Warbler is shown in the figure showing that in the winter some occur in western Southern California.