Buff-rumped Warbler Myiothlypis fulvicauda Scientific name definitions

A quick pale flash across forest streams and trails often reveals the presence of the well-named Buff-rumped Warbler. It is dark olive-brown above, paler below, with a prominent pale supercilium and broad pale rump and base to the tail. It forages near or on the ground, constantly pumping its spread tail up and down while moving it from side to side as if in slow motion. Buff-rumped Warblers are common in damp lowlands and foothills, where pairs defend territories along waterways year-round.

13·5 cm; 14·9 g. Like most others in "Phaeothlypis group", constantly pumps tail up and down, and swings it from side to side. Nominate subspecies has crown slate-grey (feathers with narrow blackish fringes in fresh plumage), nape and ear-coverts olive-grey, supercilium buff, eyestripe blackish, side of face pale olive-grey and buff, buffier on malar area; upperparts greyish-olive, contrasting pale tawny-buff lower rump and basal half of tail (prominent during tail-swinging action); distal half of tail dark olive-brown; throat and underparts whitish, washed buff on breast and flanks, with richer buff on undertail-coverts; iris dark; bill blackish; legs pale yellowish-pink. Sexes similar. Juvenile has head, upperparts (including rump), throat and breast dark brown, olive mottling on breast, obscure dull olive wingbars on greater and median upperwing-coverts, tail pattern as adult, pale buff lower underparts, bill mostly pale dusky pink. subspecies leucopygia has browner crown and upperparts than nominate, also paler straw-buff rump and upper tail, distinct olive spotting across breast, and darker cheeks and legs; veraguensis is similar to previous, but pale areas on rump and tail slightly darker and more extensive (over basal two-thirds of tail), spotting on breast less distinct; semicervina has more extensive pale colour on rump and tail, only distal quarter being dark, the buff richer than on nominate and underparts also more buff; <em>motacilla</em> has rump-tail pattern similar to last, but paler, more straw/yellow, also upperparts paler and greener, underparts whiter; significans has less pale on rump and tail than other subspeciess, only basal quarter of tail being pale buff, also is more greenish on upperparts than nominate (in these respects appears to approach subspecies boliviana of M. mesoleuca).

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Feeds mainly on insects and other arthropods. Forages by hopping (rarely walking) on ground or on fallen logs, gleaning along stream edges and damp areas of forest floor, and occasionally performing short flycatching sallies from ground; in rainy season often feeds by temporary puddles on wet forest tracks.

Song a short warble which runs into a series of 8–9 loud ringing "chew" notes; female occasionally gives short warble in reply to male's song. Usual call an emphatic "tschick".

Egg-laying in Apr–Aug in Costa Rica, and birds in breeding condition as early as Feb in Colombia; single-brooded. Pair remains on territory (which generally linear and following a watercourse) all year. Nest a bulky domed structure with side entrance, built by both sexes from various vegetable fibres, lined with finer material, placed on sloping bank by stream or path. Clutch 2 eggs; incubation period 16–17 days, occasionally 19 days; nestling period 13–14 days.