Bertoni's Antbird Drymophila rubricollis Scientific name definitions

The Bertoni's Antbird is so similar in appearance to the Ferruginous Antbird (Drymophila ferruginea) that it was not even recognized as a distinct species until the late 1980s. Although the distribution of Bertoni's is more southern, and more montane, than the distribution of Ferruginous, these two species locally are sympatric. These two antwrens are much more easily distinguished by voice than by plumage: the song of Bertoni's is a series of raspy notes, very different from the two note song of Ferruginous. Pairs and family groups, which sometimes join mixed species flocks, feed on insects usually by perch-gleaning. Bertoni's Antbirds forage in the understory in dense thickets, often in bamboo.

12·5–13·5 cm; 1 individual 10 g. Male has black crown  , long white supercilium  , broad black band through eye; lower side of head  white, speckled black; upperparts reddish yellow-brown, few black feathers on back, white interscapular patch, rump rufous; remiges brownish-black, edged paler, wing-coverts black, broadly tipped white; graduated tail dark brown to blackish-brown, broad white tips; chin white, speckled black, throat and remaining underparts  rufous. Distinguished from very similar D. ferruginea by having only few black feathers on back, somewhat paler remiges, paler underparts, browner tail longer on average. Female is paler than male, forehead and crown rufescent brown, this reduced to streaks on hindcrown, wing-covert tips tinged rufous, no white interscapular patch. Subadult male is like female, but with white interscapular patch.

SE Brazil (extreme SE Minas Gerais, Rio de Janeiro and C & E São Paulo S to W & C Paraná and NW Rio Grande do Sul), E Paraguay (Canindeyú, Alto Paraná, Caazapá) and extreme NE Argentina (N Misiones).

Little published. Feeds on insects, including lepidopteran larvae and orthopterans; probably also on spiders. Closely associated partners, individuals, or family groups forage mostly 1–15 m above ground, alone or with mixed-species flocks of other insectivores; mean foraging height in over 200 observations was 3·9 m. Active forager; progresses by short hops, separated by pauses of 1–3 seconds to scan for prey. Appears to forage almost exclusively in bamboo, and only occasionally ventures into adjacent broadleaf trees or shrubs in N portion of range; hitches from side to side along arching bamboo stems; posture mostly horizontal, with tail held at same plane or slightly cocked, often swung from side to side and occasionally flicked up to 10–20 degrees above horizontal, then slowly lowered; habitually flicks both wings. Most attack manoeuvres are perch-gleans to live bamboo leaves, or suspended dead leaves trapped in the bamboo; gleans mostly by reaching up, out or down with quick stabs of the bill, or by short horizontal lunges; also makes short (less than 30 cm) fluttering sallies to underside of overhanging vegetation. Not known to follow army ants.

Male loudsong a short series (e.g. 9 notes, 1·7 seconds) but length variable, introductory note followed by shorter, sharper note that gradually lengthens into longer harsher notes while descending slightly in pitch, intensifies initially and also softens at end; female song lower-pitched, similar in pattern to male, but intermediate notes shorter and faster in greater contrast to final long, raspy notes, also usually less intense than male song, and first note often overlaps last note of male’s. Calls include long (e.g. 0·2 seconds), somewhat harsh and complaining notes in short series of 4–6, also similar but harsher and longer (e.g. 0·3–0·4 seconds) notes in triplets.