Russet-backed Oropendola

The Russet-backed Oropendola is a large, sturdily built icterid widespread across the western and central Amazon basin, showing more subdued coloring than some of its relatives: mostly olive-brown to russet-tinged plumage rather than glossy black, with a pale, mostly yellowish or pale greenish bill. Like other oropendolas, it shows a marked size difference between the sexes, with males considerably larger and heavier than females.

Highly social, it forms noisy colonies where many long, pendulous nests hang together from the outer branches of a single tall tree, and the species' liquid, gurgling calls and dramatic male display are a familiar sound of forest edges and clearings throughout its range.

Key field marks

• Olive-brown to russet-tinged body plumage, less glossy than the Crested Oropendola
• Pale, mostly yellowish or greenish bill
• Yellow outer tail feathers, as in other oropendolas
• Marked size difference between larger males and smaller females

Similar species

• Crested Oropendola is glossier black with a more defined chestnut rump patch and pale blue eyes.
• Dusky-green Oropendola is darker and more uniformly greenish, found in a more restricted range within the Amazon basin.

Habitat

Inhabits forest edge, várzea (seasonally flooded forest), plantations, and clearings within lowland and foothill forest.

Range

Widespread across the western and central Amazon basin and adjacent Andean foothills, including Colombia, Ecuador, Peru, Bolivia, and Brazil.

Migration

Mostly resident, with local movements tied to fruiting and flowering seasons.

Behavior

Highly colonial, nesting in groups with numerous woven nests hanging from a single tree; males perform a bowing display with wings spread while giving their gurgling song to attract mates.

Voice

A liquid, gurgling, cascading song similar to other oropendolas, along with various chattering and harsh calls.

Feeding

Feeds on fruit, insects, and nectar, foraging in the canopy and at forest edges, often in small groups.

Nesting

Builds long, woven, pendulous nests hanging in colonies from a single emergent tree; polygynous mating system typical of oropendolas.