Crested Oropendola Psarocolius decumanus Scientific name definitions

Undoubtedly overall the commonest and most widespread oropendola, the Crested Oropendola occurs from Costa Rica, where the species arrived as recently as 1999, south over much of South America east of the Andes, as far as northeast Argentina. The bird’s plumage appears largely black with a chestnut rump and ventral underparts, while most of the tail is yellow, which is especially obvious in flight or from below when perched, and the irides are blue. The Crested Oropendola is principally found below 1000 m, but has been recorded to at least 2600 m in Colombia, and in some areas it appears to perform some regular seasonal movements. The species’ colonies are regularly attended by the parasitic Giant Cowbird (Molothrus oryzivorus).

Male average 47 cm, 284·6 g; female average 37 cm, 158 g. Male nominate race is black overall, with slight gloss, becoming chestnut on rump, uppertail-coverts and undertail-coverts ; a few thin feathers form small black crest; tail yellow, central feather pair black; birds from region of Bolivia, C Brazil, Paraguay and N Argentina (“maculosus”) frequently have variable number of pale yellow feathers in body, but this character sometimes shown by individuals from elsewhere (e.g. Vene­zuela); iris blue; bill is expanded into casque, and is ivory to pale yellow; legs black. Female is like male, but smaller and somewhat duller, with much of plumage brownish-tinged (not pure black); crest greatly reduced and generally not visible in field. Juvenile resembles female, but still duller, with eyes dark brownish, bill tinged brown. Races differ little: <em>melanterus</em> is more glossy black and less chestnut than nominate; insularis is smaller and more chestnut than others.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Edges and clearings of tropical, subtropical and lower montane forests, also in second growth, gallery forest (particularly in the Pantanal and in Paraguay), savanna and plantations with large trees. Over most of its range, not regularly found in unbroken primary forest. Lowlands and low hills, generally below 1000 m; nominate race mostly below 1700 m, rarely to 2600 m.

Diet fruits, insects and spiders (Araneae); also small vertebrates, such as tree-frogs (Hylidae); also floral nectar. Consumes both wild fruits (<em>Cecropia</em> , Cayaponia, Cordia) and cultivated fruits (oranges, papayas, mangos). Insects in stomach contents include beetles (of families Cerambycidae and Curculionidae) and caterpillars. Takes nectar from flowers of several trees, commonly <em>Erythrina</em> , also from the vine Combretum lanceolatum. Forages mostly in trees , in upper stratum, rarely in lower strata or on ground. Will join mixed-species foraging flocks with other icterids and jays (Corvidae).

Male song during display usually starts with low-pitched liquid notes, accelerates into variable and complex rattling crescendo, and ends with 2–3 seconds of rhythmic wing-flaps (wing-flapping noise not reliably reported for other oropendolas). Gives repeated harsh “kak-kak-kak” in alarm.

Season Jan–Jun in Venezuela and Oct–Dec in NW Argentina. Breeds in colonies of 2–43 nests, most colonies having fewer than ten nests, largest colonies reported from NW Argentina and Trinidad (where it is the only member of its genus); reported in mixed colonies with caciques and several congeners. Displaying male performs a deep bow while singing . Nest built by female, a purse 70–160 cm long (replacement nests of same female usually shorter), open at top, and having characteristic elongated pyriform shape, rather neatly woven from diverse plant fibres (strips of lianas, palm leaves, fibres from bromeliads, etc.), lined mostly with dry leaves, and suspended from high branch tip of tree, usually an isolated one, and in gallery forest (Paraguay and NE Argentina) often over river or channel; some nests in Amazonian Bolivia included blackish Marasmius rhizomorphs in the attachment, and fibres of Spanish moss (Tillandsia usneoides) also reported; females steal nest material from each other, also from nests of other birds, including Cacicus chrysopterus. Nests sometimes usurped by Piratic Flycatcher (Legatus leucophaius). Clutch 2 eggs, bluish-white, pale grey or buff with blackish spots and lines, mean dimensions 35·9 × 24·5 mm; incubation by female, period 17–19 days; chicks tended by female, nestling period 28–34 days; male parental care limited to colony-guarding. One of the most important hosts of Molothrus oryzivorus throughout much of range (records from Trinidad and Venezuela S to N Argentina); alleged record of parasitism by Molothrus bonariensis in Argentina invalid.

Not globally threatened. Common in much of range; scarcer in S of range. Recently invaded Costa Rica. Has increased in NW Argentina. Declines recorded in NE Argentina, where now rare in Misiones, and in SE Brazil, where formerly extended S to Santa Catarina. Extirpated in Cauca Valley and some other areas of Colombia. The most widespread and ecologically tolerant oropendola; apparently able to tolerate partial deforestation more than are its congeners. Present in many protected areas, e.g. Henri Pittier National Park (Venezuela), Pantanal National Park (Brazil), Amboró National Park (Bolivia) and Calilegua and Baritú National Parks (Argentina), among others. Regarded as an agricultural pest in fruit orchards and plantations in Trinidad, Venezuela, NW Argentina and other regions, and locally persecuted.