29 January 2010, El Valle, Cocle Province, Panama

Like other oropendolas, this species is polygynous. At colonies females
outnumber males by about 5:1. This was one of the species which was
studied by N. G. Smith in which he concluded that there was an advantage to
being parasitized by Giant Cowbirds, claiming that the baby cowbirds ate
botfly larva off the oropendola chicks.

Reference: Smith, N.G. 1968. The Advantage of being Parasitized. Nature
219, 690 - 694 (17 August 1968); doi:10.1038/219690a0

Two races are recognized. Ridgwayi ranges from Honduras to Ecuador. The
nominate race replaces it north into Mexico. Ridgwayi reportedly differs
slightly in the size of the casque and in overall color, but these
differences have been questioned. Males, such as this, are larger with a
larger casque cf. females. Females also lack the wispy crest of males as
seen here.

This species has been called Wagler's Oropendola and has been placed in the
monotypic genus Zarhynchus by earlier authors.

Digiscoped with Panasonic DMC-LZ5 | Nikon FieldScope 3 | 30X WA | hand-held
(no adapter)