Cocos Cuckoo

The Cocos cuckoo, Coccyzus ferrugineus, presents a striking figure with its elongated tail comprising half of its 32 to 33 cm length. Weighing approximately 70 grams, this bird is characterized by a robust, slightly curved bill, a black maxilla, and a mandible that ranges from yellow to yellow-orange with a black tip. Both sexes are similarly attired in a plumage of slate gray on the forehead and crown, transitioning to grayish brown on the upperparts, with rufous wings. The tail is a matching grayish brown above and black below, with generous white tips. A narrow blackish facial mask extends past the eye, set off by a delicate ring of yellow to orange-yellow bare skin. The underparts are a soft buffy white, leading to a rich buff on the belly and undertail coverts. Juveniles share the adult coloration but with less pronounced contrasts and a whitish throat, chest, and belly.

Identification Tips

When identifying the Cocos cuckoo, look for the distinctive long tail and the contrast between the slate gray head and the rufous wings. The facial mask and the yellow to orange-yellow eye ring are also key features. In flight, the white-tipped tail is quite conspicuous.

Habitat

This bird is endemic to Cocos Island, a lush oasis in the Pacific Ocean under Costa Rica's stewardship. It thrives across the island's diverse habitats, from sea level to the highest elevations of approximately 450 meters. These habitats include flooded bay forest, riparian forest, tropical rainforest, and tropical cloudforest.

Distribution

The Cocos cuckoo is a unique species, found nowhere else but on Cocos Island, situated some 550 kilometers off the Pacific coast of Costa Rica.

Behaviour

The Cocos cuckoo is a permanent resident of the island, favoring forest edges during the breeding season and retreating to the forest interior at other times. Its movements are typically limited to short flights, hops along branches, and brief flutters and glides within the trees.

Feeding

A diet rich in caterpillars, particularly those of the giant sphinx moth and the Orion cecropian butterfly, sustains the adult Cocos cuckoo. Juveniles are fed a diet of crickets and cockroaches. The bird employs various foraging techniques, including ground-level hunting, gleaning from understory plants, and probing in bromeliads. Occasionally, it may also consume the endemic Anolis towsendi lizard.

Breeding

Breeding occurs during the dry season from January to mid-April. Both sexes collaborate in constructing a simple stick nest without lining, usually situated on a small branch and partially concealed by leaves. While the exact clutch size is unknown, it is presumed to be one or two eggs. Incubation and fledging periods are not well documented but are speculated to align with those of related species.

Vocalization

The Cocos cuckoo's song, a guttural series of "Eeh-eeh-eeh-eeh-eeh-eeeh-eeeehh" notes, is most often heard during the breeding season, particularly from dawn until noon. However, recordings of this elusive song are rare.

Conservation status

The IUCN has classified the Cocos cuckoo as Vulnerable due to its very limited range and small population, estimated between 250 and 1000 mature individuals. The species faces threats from feral cats, pigs, goats, and deer, which either prey upon the cuckoo or degrade its habitat. Increasing tourism and climate change also pose potential risks to its survival.