A large cacique, more reminiscent of an oropendola than most other cacique species. Highly local in western Amazonia, where it is mostly associated with flooded forests. Despite its size, more frequently heard than seen. Usually seen in mixed flocks with other species of caciques or oropendolas, as well as in small groups of 3–5 individuals, foraging. Notice the large, sharp white bill, brownish upper back and crown, and the yellow tail. Rest of the plumage generally glossy black or grayish.