Pearly-breasted Cuckoo

The Pearly-breasted Cuckoo, Coccyzus euleri, is a member of the cuckoo family, Cuculidae, and is a bird of moderate size, measuring 25 to 28 cm in length, with nearly half of this being the tail. The males are slightly lighter, weighing between 45 to 53 grams, while females tip the scales at about 54 to 61 grams. Both sexes share the same plumage, which is a testament to their shared roles in the species' lifecycle.

Identification Tips

This species can be identified by its stout, slightly decurved bill, with a brown to black maxilla and a yellow to orange mandible tipped in black. The adult's upperparts are a grayish brown with a light bronze sheen, and the wings are similarly colored but with white on the inner webs of the primaries. The tail is a study in contrast, with the upper surface being grayish brown and the underside varying from brownish gray to black with white spots. A distinctive dark gray facial "mask" extends past the eye, which is encircled by a narrow ring of bare skin that may appear black, yellow, or red. The underparts are a pearly grayish white, transitioning to white on the belly and light pearly gray on the undertail coverts. Juveniles resemble adults but lack the facial mask and have only hints of white on the tail.

Habitat

The Pearly-breasted Cuckoo is found in a variety of wooded landscapes, primarily inhabiting humid evergreen primary forests, gallery forests, and secondary forests during the breeding season. In non-breeding areas, it frequents terra firme forests, sandy-soil woodlands, scrublands, mangroves, cerrado, and semi-deciduous forests.

Distribution

This cuckoo breeds in Argentina, Brazil, French Guiana, Paraguay, and Venezuela, and is present as a non-breeder in Bolivia, Ecuador, Guyana, and Suriname. Sightings in Colombia and Panama suggest potential expansion of its range, though these are not yet fully confirmed.

Behaviour

The migration patterns of the Pearly-breasted Cuckoo are not entirely understood. Birds from the southern part of their range migrate north for the austral winter, while those north of the equator appear to be non-migratory. Solitary in nature, they occasionally join mixed-species foraging flocks.

Song & Calls

The primary song of the Pearly-breasted Cuckoo is a series of loud, frog-like "kuoup" notes, often repeated in a sequence. Additionally, it produces a "Rattle Call" reminiscent of the yellow-billed cuckoo's call.

Breeding

Breeding phenology is not well-documented, but the species is known to build a loose platform nest of thin dry sticks in tree forks. Clutch size typically ranges from two to four eggs, and while incubation periods and fledging times are not precisely known, they are believed to be similar to those of other Coccyzus cuckoos.

Diet and Feeding

The Pearly-breasted Cuckoo forages from the forest mid-story to the canopy, primarily preying on caterpillars. It is usually seen foraging alone.

Conservation status

The IUCN has classified the Pearly-breasted Cuckoo as Least Concern due to its extremely large range and presumed stable population. However, it is likely that deforestation and habitat degradation in the Neotropics have impacted numbers locally and regionally. In northeastern Brazil, the species is hunted for food, which may also affect its population.