Dark-billed Cuckoo

The dark-billed cuckoo is 25 to 28 cm (9.8 to 11.0 in) long, about half of which is the tail. Males weigh about 42 to 54 g (1.5 to 1.9 oz) and females about 50 to 66 g (1.8 to 2.3 oz). Males and females have the same plumage. They have a gray crown and nape and grayish brown upperparts. Their wings are a darker grayish brown with no rufous. The upper surface of their tail is brown; the underside of the central pair of feathers is brown with black tips, the next pair blackish with narrow white tips, and the rest black with wide white tips. Their face is gray with a wide black "mask" past the eye, which is surrounded by a narrow ring of citron yellow, olive yellow, or gray bare skin. Their underparts are pale buff with the breast somewhat darker than the rest; the sides of the breast and flanks are gray. Juveniles are similar to adults but duller, with a brown crown and nape, gray tips on the tail feathers, and sometimes rufous in the wings.

The dark-billed cuckoo is found regularly throughout much of South America except in Chile, where it has occurred as a vagrant. It is also resident on the Galápagos Islands. In addition to Chile, it has occurred as a vagrant in Clipperton Island, Panama, Trinidad, the Falkland Islands, Grenada, Florida, and Texas. It inhabits a wide variety of landscapes including the interior and edges of tropical deciduous, gallery, and mature secondary forest plus mangroves. It is generally a bird of the lowlands below 950 m (3,100 ft) but has been documented as high as 3,600 m (11,800 ft).