Yellow-backed Oriole

Yellow-backed orioles are a yellow-bodied, sexually monomorphic species. They average 21.5 cm (8.5 in) in length from beak to tail; making it a relatively medium-sized oriole species. Exposed skin and claws are bluish-black; in adults, the bill is black, with the base of the mandible becoming bluish-grey. Adult males display strongly contrasting yellow and black plumage. The wings, tail, shoulders, throat, and face are all black; by contrast, the back and underparts are an extremely bright yellow. Adult females closely resemble males, but yellow parts appear slightly greenish. Despite differences in plumage coloration between sexes, it is likely that this species is extremely difficult to sex in the field. Immature yellow-backed orioles resemble adult females in overall pattern, but are greener; additionally, the flight feathers, which are black in females, are dark brown. Immature yellow-backed orioles are easily distinguished from adult females by their olive eye-line. Similar species include the South American yellow oriole (Icterus nigrogularis).

Yellow-backed orioles are found throughout Central America and northern South America. In particular, the species is divided into three allopatric populations. One population, designated as the subspecies I. c. giraudii, is endemic to southern Central America, including Nicaragua, Panama, and Colombia. The northernmost populations comprise the subspecies I. c. chrysater and I. c. mayanensis; these subspecies are found in northern Central America and in southern Mexico. The species is found in Belize, Colombia, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, and Venezuela. Yellow-backed orioles are able to tolerate a wide variety of habitats, but prefer open, mixed pine-oak woodlands and dry scrub forest. This species has also been sighted in banana plantations. It has occasionally colonized lowland deciduous forest. This species is usually found in regions that are less than 900 m (3,000 ft) in altitude, though in Central and South America populations are often seen residing at elevations greater than 1,000 m (3,300 ft). The upper altitude limit for populations observed in the wild appears to be about 3,000 m (9,800 ft).

Yellow-backed orioles are monogamous; like many species of the genus Icterus, they breed once a year with a single mate. The nests of this species are shallow, dangling baskets that are usually hung from the edge of a tree limb. Members of this species appear to prefer to attach nests to the tips of palm fronds. Nests are usually woven of fine grasses, giving them a springy texture (Wetmore et al. 1984). Nests of this species are normally hung in the canopy of mature trees that are at least 7 m (23 ft) in height. The eggs of this species are whitish, with purple scrawlings that are concentrated near the broad end of the egg. The eggs are commonly marked with evenly distributed brown lines.