Dark-billed Cuckoo

The Dark-billed Cuckoo, Coccyzus melacoryphus, is a bird of modest size, measuring from 25 to 28 centimeters in length, with nearly half of that being its tail. The males of the species typically weigh between 42 to 54 grams, while females are slightly heavier, ranging from 50 to 66 grams. Both sexes share the same plumage, characterized by a gray crown and nape, with upperparts of a grayish brown hue. Their wings are a darker shade of the same color, lacking any rufous tint.

Identification Tips

Upon closer inspection, one can observe the bird's tail, which is brown on top, with the underside of the central feathers being brown with black tips. The adjacent pair is blackish with narrow white tips, and the remaining feathers are black with broad white tips. The face of the Dark-billed Cuckoo is gray, adorned with a wide black "mask" extending past the eye, which is encircled by a ring of citron yellow, olive yellow, or gray bare skin. The underparts are a pale buff, with the breast a shade darker and the sides of the breast and flanks a gray tone. Juveniles resemble adults but are generally duller, with a brown crown and nape, gray-tipped tail feathers, and occasionally, rufous in the wings.

Habitat

This species is known to inhabit a diverse array of landscapes, including the interior and edges of tropical deciduous, gallery, and mature secondary forests, as well as mangroves. It is predominantly a lowland bird, typically found below 950 meters, but has been recorded at elevations as high as 3,600 meters.

Distribution

The Dark-billed Cuckoo is a widespread resident across mainland South America, with the exception of Chile, where it is considered a vagrant. It also calls the Galápagos Islands home. Beyond its regular range, it has been spotted as a vagrant in locations such as Clipperton Island, Panama, Trinidad, the Falkland Islands, Grenada, Florida, and Texas.

Behaviour

The Dark-billed Cuckoo exhibits residency year-round in the Galápagos Islands and west of the Andes in Colombia, Ecuador, and possibly Peru. Populations in southern Brazil, Uruguay, and Argentina are migratory, heading north during the austral winter. Similarly, those breeding in the Venezuelan Llanos migrate southward after nesting, with the species present in most of the Amazon basin only during the austral winter.

Song & calls

The vocal repertoire of the Dark-billed Cuckoo includes a song described as six to eight resonant, buzzy kazoo-like notes or a ventriloquial ga-ga-ga-go-go. Another song may be a descending series of guttural notes. Additionally, it emits a dry-sounding buzz, articulated as "dddddrr."

Breeding

The nesting behavior of the Dark-billed Cuckoo involves constructing a flat platform of sticks within a tree or bush. Clutch size varies geographically, with two or three eggs being common in most of its range, while in Argentina, three to four eggs, and occasionally five, are more typical. The eggs are a greenish blue, and incubation, which begins with the laying of the first egg, results in asynchronous hatching and size variation among the young.

Diet and Feeding

The diet of the Dark-billed Cuckoo is predominantly composed of insects, both in their adult and larval stages.

Conservation status

The IUCN has classified the Dark-billed Cuckoo as Least Concern. It boasts an extremely large range and, although the exact population size is unknown, it is believed to be stable without any immediate threats. The species is considered fairly common throughout its range.