This large cuckoo with its heavy, curved bill, is endemic to the island of Hispaniola, where it is now almost certainly more or less confined to the Dominican Republic, and even here the species appears to be in decline. In consequence, BirdLife International currently considers it to be Endangered. The Bay-breasted Cuckoo is principally gray above with a reddish-brown primary patch, throat and breast, and a glossy black tail with broad white tips to the feathers. Females are slightly larger than males. This cuckoo is mainly found in the lowlands and foothills, and it appears to prefer the narrow transition zone between dry forest and moist broadleaf forest, but the species has also been reported from other forested habitats. It is most easily located by its most distinctive vocalization, a forceful cua, often followed by accelerating u-ak-u-ak-ak-ak-ak-ak-ak ak-ak.