Red-billed Woodcreeper Hylexetastes perrotii Scientific name definitions

At least in the past, sometimes considered conspecific with the similar Bar-bellied Woodcreeper (Hylexetastes stresemanni) of southern Amazonia, the taxonomy of these woodcreepers is still somewhat confused. Here, Red-billed Woodcreeper has recently been split from Uniform Woodcreeper (Hylexetastes uniformis), also of southern Amazonia, based largely on genetic differences as well as minor morphological and plumage differences. All taxa of Hylexetastes possess a red bill, although this is not always easily appreciated in the dim forest light. The Red-billed Woodcreeper has otherwise generally unmarked solid brown plumage though with whitish lores and a frosty white moustachial stripe. It occurs north of the Amazon, from eastern Venezuela to northern Brazil, and seems to be more or less confined to the interior of terra firme forests, including those on sandy soils. Like other large woodcreepers, its diet is quite varied including both vertebrates and invertebrates, and Red-billed Woodcreeper is often dominant over other woodcreepers at army ant swarms.

25–30 cm; male 112–137·5 g, female 110–145 g. Large, heavy-bodied woodcreeper with large head, short but massive bill, heavy legs and feet; relatively short tail often excessively worn, possibly a result of foraging close to ground. Has whitish lores, frosty white moustachial stripe from lores back across head just below auriculars, olive-brown throat with whitish to buffy center; otherwise largely uniform, smoky brown to olive-brown above (including wing-coverts), with remiges, rump and tail bright rufous to rufous-chestnut, primary tips dusky; breast grayish-brown, belly buffy brown, undertail-coverts tending to be more rufescent; about half of individuals have indistinct dusky gray bars on belly and undertail-coverts; iris brown to reddish-brown, even red; bill wine-red to brownish; legs and feet shades of green or olive, often with brown or gray intermixed. Distinguished from Bar-bellied Woodcreeper (Hylexetastes stresemanni) by more weakly barred underparts, pale moustachial stripe; from somewhat similar Amazonian Barred-Woodcreeper (Dendrocolaptes certhia) mainly by bold facial markings and noticeably stouter body. Sexes similar. Juvenile is similar to adult, but crown weakly streaked, on average more heavily barred and possibly more rufescent below, eyes dark gray, shorter bill dusky to blackish, sometimes with pale lower mandible.

Close to Bar-bellied Woodcreeper (Hylexetastes stresemanni) and possibly conspecific (see below). Previously considered conspecific with Uniform Woodcreeper (Hylexetastes uniformis), but split largely on the basis of genetic (1 Harvey, M. G., G. A. Bravo, S. Claramunt, A. M. Cuervo, G. E. Derryberry, J. Battilana, G. F. Seeholzer, J. S. McKay, B. C. O'Meara, B. C. Faircloth, S. V. Edwards, J. Pérez-Emán, R. G. Moyle, F. H. Sheldon, A. Aleixo, B. T. Smith, R. T. Chesser, L. F. Silveira, J. Cracraft, R. T. Brumfield, and E. P. Derryberry (2020). The evolution of a tropical biodiversity hotspot. Science 370:1343–1348. Close ), ecological (2 Azuaje-Rodríguez, R. A., J. D. Weckstein, J. H. Dispoto, S. Patel, J. A. Cacioppo, J. M. Bates, S. Marques Silva, and A. Aleixo (2020). Molecular Systematics of the Amazonian endemic genus Hylexetastes (Aves: Dendrocolaptidae): taxonomic and conservation implications. Ibis 162:119-136 Close ), plumage, and morphological differences (3 Derryberry, E., Seddon, N., Claramunt, S., Tobias, J.A., Baker, A., Aleixo, A. and Brumfield, R.T. (2012). Correlated evolution of beak morphology and song in the Neotropical woodcreeper radiation. Evolution 66(9): 2784–2797. Close ); the two share vocal similarities, and there is still a lack of behavioral data about the two taxa; intermediates not known, but total number of specimens small. In a recent study, Azuaje-Roddríguez et al. (2 Azuaje-Rodríguez, R. A., J. D. Weckstein, J. H. Dispoto, S. Patel, J. A. Cacioppo, J. M. Bates, S. Marques Silva, and A. Aleixo (2020). Molecular Systematics of the Amazonian endemic genus Hylexetastes (Aves: Dendrocolaptidae): taxonomic and conservation implications. Ibis 162:119-136 Close ) found that not only was Red-billed Woodcreeper more closely related to Bar-bellied Woodcreeper than to the previously conspecific Uniform Woodcreeper, but was also predicted to occupy different areas of the Amazon Basin than the other taxa.

Northeastern Amazonia in eastern Venezuela (Río Yuruán, in northeastern Bolívar), the Guianas and northern Brazil (lower Rio Negro and central Roraima east to Amapá).

Some information presented here may refer to Uniform Woodcreeper (Hylexetastes uniformis), but is presumably similar in present species. Primarily humid terra firme forest in Amazonian lowlands and hilly Guianan interior; sometimes occurs in gallery or seasonally flooded forests or those growing on sandy soils; also encountered rarely in savanna forest in Surinam. Mainly in interior of tall primary forest, but sometimes at edges and even in selectively cut forest; avoids younger second growth, but uses older second growth on occasion. Largely restricted to lowlands.

Some information presented here may refer to Uniform Woodcreeper (Hylexetastes uniformis), but is presumably similar in present species. Diet mostly small arthropods; larger items, including small vertebrates, sometimes taken. Prey often quite small (including ant and wasp larvae), but this may reflect availability rather than preference; small prey sometimes left for other species. Stomach contents have included spiders, beetles, and Hymenoptera (both ants and wasps). Centipedes (Chilopoda), spiders, scorpions, and katydids (Tettigoniidae) often taken over army ants, cockroaches (Blattodea) only rarely so; both frogs and snakes recorded as being eaten, and winged ants taken during hatches. Forages singly and in pairs. Regularly associates both with army-ant swarms and with mixed-species flocks. When foraging over ants, uses near-vertical trunks of medium to large size (5–50 cm), generally perching either below 2 m (often less than 1 m) or at 10–15 m above ground; most prey taken in clumsy sallies to ground, but significant percentage gleaned from trunks, limbs, or foliage. Away from ant swarms, often forages among mixed-species flocks in middle to upper levels of forest, on trunks of large trees, where gleaning or pecking probably more important than sallying; occasionally seen to follow flocks of Red-throated Caracara (Ibycter americanus), presumably for prey they flush. Sometimes digs in rotten wood, termite nests and, occasionally, in epiphytes or debris, for which massive bill seems well adapted. Generally looks outwards when hitching or perched, rather than peering inwards at trunks as do Xiphorhynchus. Despite clumsy movements and often sluggish behavior, is dominant over all other woodcreepers and all thamnophilid antbirds, probably because of its large size; forages low in best positions over sides and front edge of ant swarms, and regularly chases and supplants conspecific and other woodcreepers over swarms, excluding Black-banded Woodcreeper (Dendrocolaptes picumnus) at one site, and supplanting species as large as Strong-billed Woodcreeper (Xiphocolaptes promeropirhynchus); only one observation of displacement by another species, a forest-falcon (Micrastur).

Some information presented here may refer to Uniform Woodcreeper (Hylexetastes uniformis); known to be very similar, but future work needed to evaluate the vocalizations of these two formerly conspecific species. Song, given almost exclusively at first or last light from canopy of tall tree near centre of territory, but occasionally during day in territorial interactions, a loud, ringing series of 2–6 whistles each ca. 1 second long and almost disyllabic, first part longer and sometimes lower in pitch, second higher and more emphasized, notes described as “wreeeeeét” or “erweeék” and song as “kyuu-hee, kyuu-hee…” or “hoooooreet, hoooooreet, hoooreet, hooreet,” series often repeated only few times; heard at close range, song less noticeably disyllabic and not descending like song of Strong-billed Woodcreeper (Xiphocolaptes promeropirhynchus); both members of pair apparently sing, but at slightly different pitch. Various calls described as snarling “screee-wip,” “nnyeah,” and “nyip, nyeek, nyeek, weeweweweip,” the last in response to tape playback of song; also growling series of “cag” notes, faint grunting “whinh, whaih, whaih” directed at nearby Xiphocolaptes, and faint disyllabic whistles by dependent young. Quality of calls, and even songs, similar to that of Xiphocolaptes.

Some information presented here may refer to Uniform Woodcreeper (Hylexetastes uniformis), but is presumably similar in present species. Breeding biology is little known; eggs and most aspects of breeding biology undescribed. Birds with gonads greatly enlarged in early October and moderately enlarged in late March in Surinam; probably breeds in dry season, e.g. June–September near Manaus (Brazil), where single dependent fledglings seen beginning of August to October; carrying bark chips to cavities in both late February and mid-August, and apparently brooding at former nest in mid-March, in French Guiana. Nests observed during construction were in cavities near tops of large stumps. Fledglings may remain with parents until May of following year (Manaus); fledged young of year dominant over one parent (apparently male), but dominated by other (apparently female). Has been speculated that only 1 egg laid, and that breeding success low.

Its conservation status has not been assessed since it was recently split from Uniform Woodcreeper (Hylexetastes uniformis), but it is not thought to be globally threatened. Status poorly known; probably uncommon to rare throughout its range, and apparently present at most sites in low densities and on large, mutually exclusive territories. In Brazil, rare to uncommon at well-worked sites in reserves north of Manaus, in northern Roraima, and at sites in Amapá; rare to uncommon in the Guianas, and known in Venezuela from only two records. Densities at site near Manaus estimated at 3.5 birds/100 ha. Appears to be highly sensitive to habitat modification, as evidenced by observations of its abandoning ant swarms that move into second growth, and its disappearance from both selectively logged sites and small forest fragments after isolation; reappearance at an isolated fragment indicates, however, that it will cross areas of unsuitable habitat to locate active ant swarms. An indicator species for tropical lowland evergreen forest in northern Amazonia.