Chestnut-headed Oropendola, Psarocolius wagleri

Chestnut-headed Oropendola, Psarocolius wagleri. Photograph courtesy of Dr. Tom Bartol, Carlsbad, California, taken in the coastal region of Costa Rica, February 2016.

Background and Identification

The Chestnut-headed Oropendola, Psarocolius wagleri, is a member of the Icteridae Family of Troupials and Allies that includes Grackles, New World Blackbirds, and Orioles. Easily identified by a pale yellow beak and bright blue iris, this species is found mainly in Central America. Formerly, this species was considered monotypic because of its unique bill shape compared to other individuals in the genus Zarhynchus, but recent genetic analysis suggests that it belongs to a clade containing the Andean oropendolas and now has two recognized subspecies. The two subspecies are Psarocolius wagleri and Psarocolius wagleri ridgwayi. The former species has a more northern distribution, and the latter tends to inhabit more South American countries. In Mexico, this species is known as Conoto de Cabeza Castaña.

The Chestnut-headed Oropendola is a sexually dimorphic species, which is common in most Oropendola species. Males are larger than females. The average male length is 35 cm (13.8 inches), and the average female length is 28 cm (11.0 inches). Females that have been measured in the field have an average body mass of 113 g (4.0 oz), and males can have masses almost twice as heavy (the largest recorded weighted 214 g (7.5 oz)). Both sexes have long, conical, pale bills and bright yellow tails. Males often have head plumage that extends down the back of their neck, brown or black. The body and wings are black with a bluish gloss, and females are slightly duller than males. Juveniles have brown eyes (lack bright blue iris) and have some yellow forehead feathers.

Habitat and Geographical Range

The Chestnut-headed Oropendola inhabits tropical and subtropical lowland forests, particularly in the canopy and along the forest edges. They are often found in lowland evergreen forest thickets and bushes along the edges of forests in humid environments. They consume arthropods, small birds, small invertebrates, and seasonal fruits and seeds when available. This species is highly social and often seen in small groups, foraging in the upper levels of the forest or near rivers and swamps.

Although the two separate subspecies often inhabit slightly different geographical ranges, both are typically found from southern Mexico through Central America and into northern parts of South America, including Colombia and Ecuador. In Mexico, they have a limited distribution within the Atlantic Slope in the southern States of Veracruz, Puebla, and Chiapas, at elevations below 1,200 m (3,940 feet).

Common Misidentifications

The Chestnut-headed Oropendola might be confused with the Montezuma Oropendola, Psarocolius montezuma, which also has a colorful head but is larger and has a more prominent chestnut-colored plumage extending further down the body. Another species it might be mistaken for is the Crested Oropendola, Psarocolius decumanus, which has a more uniformly dark body and lacks a bright chestnut head.

Conservation Status

From a conservation perspective the Chestnut-headed Oropendola is currently considered  to be of Least Concern with stable, widely distributed populations. Conservation efforts focused on preserving tropical and subtropical forests are crucial for maintaining stable populations of this and many other forest-dependent species.