Humaita Antbird Myrmelastes humaythae Scientific name definitions

Endemic to western Amazonia, Humaita Antbird is a very poorly known and only recently recognized species. Previously, it was considered conspecific with the more widespread Spot-winged Antbird (Myrmelastes leucostigma), in common with several other taxa recently elevated to species status. Although principally separated on the basis of clear vocal differences from the rest of the complex, plumage differentiation also exists, with male Humaita Antbird having an olive-brown cast to the crown and mantle, and being overall paler gray, especially over the underparts, while the female has the entire head brown. As a result of its long history as a subspecies, its habitat requirements, ecology and behavior are still almost unknown, although these are not likely to differ substantially from other members of the Spot-winged Antbird species complex.

14–16 cm. A typical member of the M. leucostigma species complex; compared to most other taxa, adult male  is paler throughout, with crown and upperparts tinged olive-brown, and like other taxa has wings and tail blackish grey, wing-coverts  broadly tipped white; female  has head brown, but is otherwise like other species in the complex in having wings and tail blackish brown, wing-covert tips  pale cinnamon-rufous, sides of head grey, throat and underparts tawny, paler on throat and belly, and becoming olive-brown on flanks and undertail-coverts.

SW & C Amazonian Brazil (lower R Japurá E to lower R Negro and, S of R Amazon, E to R Madeira) and extreme N Bolivia (Pando).

Understorey and floor of humid, lowland evergreen forest; usually associated with dense understorey vegetation along forest streams (igarapés in Brazil) or in low-lying, poorly drained areas inside terra firme or transitional forest; occasionally recorded in seasonally flooded forest.

No dietary data available. Little information published, but most facets of its foraging behaviour and ecology are probably very similar, if not identical, to those of M. leucostigma (which see).

Loudsong similar to that of formerly conspecific M. leucostigma, but is lower-pitched, rises over most of its length, with only a slight declination at the terminus; compared to M. brunneiceps, present species is faster-paced at start, accelerating at first before decelerating in conclusion (versus accelerating throughout), and lower-pitched, but increasing over first quarter, then generally remaining even-pitched (vs flat, before declining slightly over final third); from M. rufifacies differs in that latter accelerates throughout, with clearly downslurred notes that become frequency-modulated, higher-pitched overall and notes shorten (rather than lengthening) with longer inter-note intervals (shorter in present species). No differences reported to date between present species and others in long call, short call or rattle.

Not globally threatened (Least Concern). Uncommon throughout most of its range, e.g. known from comparatively few localities (c. 4) in Bolivia, although see also M. rufifacies. Known from Humaitá Reserve, in Brazil. Regions inhabited by species also encompass extensive areas of intact habitat which are not formally protected, but seem unlikely to be threatened by development in the near future.