The Palm Warbler differs from other member of its genus by feeding primarily on the ground or in short shrubs and trees and in being essentially sexually monomorphic. Two subspecies exist and inhabit separate breeding grounds but overlap on their wintering grounds. The Western Palm Warbler (S.p. palmarum) nests roughly west of Ottawa, Ontario, and winters along the southeastern coast of the U.S. and in the West Indies. The Yellow Palm Warbler (S.p. hypochrysea) nests east of Ottawa and winters primarily along the Gulf Coast.
Adult Male (spring/summer)
Head has rufous crown or cap; the supercilium is yellow becoming dull yellow to gray behind eye; dark brown to tan lores and eyeline; tan auriculars; yellow submoustachial stripe; tan malar stripe and yellow chin. The nape is tan or dull brown. The back, scapulars, tertials, and rump are tan or dull brown with a faint yellow wash. The uppertail coverts are dull brown with a brighter yellow wash. Wings are olive brown with low contrast wingbars. The throat is yellow; the belly is dull yellow and the flanks are dull yellow with fine rufous streaking. The undertail coverts are always yellow. The tail shows distinct white terminal band and black, squared base from below and from above shows small white corners on a black tail.
Adult Female (spring/summer)
Similar to adult male but males tend to show more chestnut on the crown.
Juvenile
Nonbreeding and immatures have paler yellow undertails, a dull brown crown, and feint streaking on the breast. ‘Western’ individuals have whitish bellies and a pale supercilium.
General:
Medium size warbler with a chestnut crown. Length: 12-14cm. Wing: 20-21cm. Weight: 7-13grams.
Behaviour:
The Palm Warbler is a habitual and distinctive ‘tail pumper’ as it forages low to the ground or on the ground. It hops and well as runs on the ground.
It is not restricted to terrestrial feeding and can be found in trees, especially budding trees in the spring and singing perches on breeding grounds. Forages for insects and for seeds and fruits in fall and winter.
Habitat:
Favours bogs and fens of the Boreal Forest and wooded margins of spruces or tamaracks, which provide singing perches. As well, partly open situations with scattered trees and heavy undergrowth, usually near water. Heavily shaded bogs are avoided, as are bogs overgrown with shrubs. During migration can be found in a variety of woodland, thickets, and second growth, on the ground in savannah and open fields.
Information:
The Palm Warbler’s name is a misnomer, as this species shows no inclination to use palms and only occurs in habitats dominated by them in portions of its wintering habitat. It moves north early in the spring and returns south late in the fall. The nest is an open cup of weed stalks, grasses, bark shreds, ferns, and rootlets, lined with fine grasses, hair and feathers. It is placed in sphagnum moss at the base of trees. Clutch is 4-5 creamy white with dark speckles around large end eggs.
Similar species:
Prairie Warbler, Yellow Warbler, Cape May Warbler, Yellow-rumped Warbler, Kirtland’s Warbler.
Conservation Status:
Listed as Least Concern. Populations are stable.
Capture Rates:
A very rare bird for the Vancouver area with captures limited to a single hatch year bird in September.
Molt Summary:
PF: HY partial; PB: AHY complete; PA limited.
Preformative molt usually includes all med and gr covs and often the greater alula, but no terts or rects. PA limited to head feathers.
Juveniles have upperparts and underparts grayish with dusky streaking, and buffy wing bars. Juv M=F.
First fall birds like this HY in September are similar to female Yellow-rumped (Myrtle) Warblers with the pale throat wrapping around behind the auriculars and dull plumage with faint, diffuse streaking and brown back. Differs in face with prominent, long supercilium, darkish cap, yellow undertail coverts and long white tail with wide black base.
Tail is long and shows distinct white terminal band and black, squared base.
The preformative molt is partial and includes all lesser, median and greater coverts but no flight feathers (primaries, secondaries or rectrices) – the molt limit indicated between the outer greater covert and inner primary covert (red arrow). Notice also the very narrow and tapered retained juvenal primary coverts.
Tail shape should always be used with caution due to a) individual variation, b) the possibility of accidental loss and replacement (adventitious molt), and c) in Setophaga warblers all age classes can show rounded retrices.
The amount and extent of white on the outer rectrices (R5 & R6 in the photo below) is also age (and sex) related in Setophaga warblers and is less extensive in HY/SY birds not extending to the inner rectrices.