the palm warbler , dendroica palmarum , is a small songbird of the new world warbler family .
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 breed in open coniferous bogs and edge east of the continental divide , across canada and the northeastern united states .
these birds migrate to the southeastern united states , the yucatn peninsula , islands of the caribbean , and eastern nicaragua south to panama to winter .
they are one of the earlier migrants to return to their breeding grounds in the spring , often completing their migration almost two months before most other warblers .
palm warbler has been recorded as a vagrant to iceland .
palm warbler nests take the form of an open cup , usually situated on or near the ground in an open area .
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 .
