Olive-backed woodcreeper

The olive-backed woodcreeper (Xiphorhynchus triangularis) is a species of bird in the subfamily Dendrocolaptinae of the ovenbird family Furnariidae. It is found in Bolivia, Colombia, Ecuador, Peru, and Venezuela.

The olive-backed woodcreeper is 19.5 to 25 cm (7.7 to 9.8 in) long, males weigh 40 to 52 g (1.4 to 1.8 oz) and females 32 to 48 g (1.1 to 1.7 oz). It is a medium-sized member of genus Xiphorhynchus, with a slightly decurved bill. The sexes have the same plumage. Adults of the nominate subspecies X. t. triangularis have a finely streaked face with a buffy supercilium and eyering. Their crown and nape are blackish brown with pale buff elongated spots. Their back, wing coverts, and rump are bright olive to brownish olive. Their upper back has scattered buff streaks. Their uppertail coverts are cinnamon to rufous-chestnut. Their flight feather have cinnamon to rufous-chestnut inner webs and bright olive outer webs with dusky tips on the primaries. Their tail is dark rufous-chestnut. Their throat is buffy white with a blackish brown scaly appearance. Their underparts are a slightly lighter olive than their upperparts. Their breast has many buffy whitish spots that become more triangular on the belly. Their flanks are plain, their undertail coverts have thin streaks, and their underwing coverts are ochraceous. Their iris is dark brown, their maxilla horn-black and whitish to bluish ivory on the side, their mandible gray with paler spots on the side, and their legs and feet blue-gray to gray with a faint olive cast. Juveniles are similar to adults but duller overall and with smaller spots on the breast.

Subspecies X. t. hylodromus has brighter olive brown upperparts than the nominate; its secondaries are darker and less reddish, its throat paler with thinner scaling, and its underparts lighter, more greenish olive, and more heavily spotted. Subspecies X. t. bangsi has more rufescent (less olive) upperparts than the nominate, its crown spots are larger, its back is more distinctly streaked, its throat is more whitish with olive, not blackish, scaling, its underparts' spots are smaller and are replaced with narrow streaks on the belly, its undertail-coverts are more rufescent with finer streaks, and its bill is whitish with black only on the base and tip of the maxilla. X. t. intermedius is intermediate between the nominate and bangsi, with slightly browner upperparts and paler and browner underparts than the nominate.