Chestnut-headed Oropendola Psarocolius wagleri Scientific name definitions

The Chestnut-headed Oropendola is found from Middle America, where it ranges from southeast Mexico south over the Caribbean slope south to South America, as far as northwest Ecuador. Adults are largely black with a chestnut head, rump, and ventral underparts, a yellow tail (except for the dark central feathers), and bright blue eyes. The all-pale bill possesses a noticeable casque and in flight the species appears strikingly long-winged. This oropendola is sometimes classified in its own genus, Zarynchus, based on the bird’s small size, large frontal shield, and long primaries, while the species’ bowing courtship display is also quite unlike those of other oropendolas.

Male average 35 cm, 214 g; female average 28 cm, 113 g. Slightly crested. Male nominate race has dark purplish-chestnut on head and down to central breast ; body and wing black with bluish gloss, becoming dark chestnut on rump and uppertail-coverts, rear flanks to undertail-coverts (and sometimes thighs) chestnut; tail yellow, central feather pair black, outer rectrices with black edges; iris pale blue; bill is expanded into swollen casque, and is ivory-coloured, sometimes with slight greenish tinge, tip and band along cutting edge pale bluish to grey; legs black. Female is like male, but smaller, with duller colours. Juvenile is duller than adult, eyes brownish (or even brownish and blue), bill brownish, some yellow feathers in forehead. Race <em>ridgwayi</em> is very like nominate, but has chestnut parts of plumage paler.

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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.

Small vertebrates (frogs and lizards), also insects and other arthropods; also fruit and nectar of large flowers, e.g. of balsa. Orthopterans and beetles (Coleoptera) found in stomach contents. Often forages high in canopy. Probes and gapes in epiphytes.

Song short, but variable, consists of low “pop” sounds followed by harsh, crashing noises (likened to sound made by a machete cutting vegetation). Frequent call (Costa Rica, Panama) a liquid, low-pitched “waku-waku”. Male produces audible wing noise in flight.

Season Jan–Jun. Polygynous. Colonial , with 15–60 (exceptionally 130) nests per colony, often located on several isolated trees, e.g. colony spread over seven Cuban royal palms (Roystonea regia) in Panama, but in Mexico more often in a single tree; often in mixed colonies with Cacicus cela and P. decumanus in S of range (S from Panama). Nest built by female, a purse 60–120 cm long, open at top, woven from diverse plant fibres such as Tillandsia, strips of lianas, palm leaves, etc., lined with pieces of dry and green leaves, suspended from branch tip of variety of plants, from palms (native and exotic) to alder trees (Alnus acuminata) in Costa Rican highlands; if unmolested, may nest near buildings or road (e.g. in former Panama Canal Zone); some colonies built in trees having nests of aggressive wasps (of genus Synoeca or Stenopolybia). Clutch 2 eggs, pale blue with brownish-black markings, mean dimensions 32·6 × 21·9 mm; incubation by female, period 17 days; chicks fed by female, nestling period up to 35 days; males guard and defend colony. Nests parasitized by Molothrus oryzivorus.