The yellow-billed cacique (Amblycercus holosericeus) is a species of bird in the family Icteridae. It is found in Mexico, every Central American country, Bolivia, Colombia, Ecuador, Peru, and Venezuela.
Taxonomy and systematics
The yellow-billed cacique was formally described in 1830 with the binomial Sturnus holosericieus. In 1851 Jean Cabanis erected the genus Amblycercus with it as the type species. For part of the twentieth century it was assigned to genus Cacicus but by the end of the century had been firmly placed back in Amblycercus. It is basal to the oropendolas and caciques but is not closely related to any of them.
The yellow-billed cacique is the only member of its genus and has these three subspecies:
Some authors have suggested that A. h. australis might warrant full species status. The Clements taxonomy draws some distinction within the species, calling A. h. australis the "yellow-billed cacique (Chapman's)" and grouping the other two subspecies as the "yellow-billed cacique (Prevost's)".
Description
Yellow-billed cacique males are about 21.5 cm (8.5 in) and females about 20.5 cm (8.1 in) long. Males of subspecies A. h. holosericeus and A. h. flavirostris weigh an average of 69 g (2.4 oz) and females 53 g (1.9 oz). Males of subspecies A. h. australis weigh an average of 50 g (1.8 oz) and females 47 g (1.7 oz). Adult males of all three subspecies are entirely black and females are a slightly slaty black. Both sexes have a pale yellow iris and gray legs and feet. Juveniles are duller than adults and have a dark iris. All subspecies have a long bill whose tip is chisel-shaped. That of the nominate subspecies A. h. holosericeus is yellow, that of A. h. flavirostris is a brighter yellow, and that of A. h. australis is more slender than the others' and is...
