Black-billed Cuckoo

The Black-billed Cuckoo, Coccyzus erythropthalmus, is a slender bird with a long, graduated tail and a black, slightly downcurved bill. Adults exhibit a brown upper body and white underparts, while juveniles are more subdued in color with potential rufous wing markings. Notably, adults have a narrow, red orbital ring, contrasting with the yellow ring of juveniles. The species is distinguished by its zygodactylous feet and, in the case of chicks, sparse white down and black skin.

Identification Tips

When identifying the Black-billed Cuckoo, look for the following characteristics:

• Total body length: 280–320 mm (11–12.6 in)
• Mass: 45–55 g (1.6–1.9 oz)
• Wingspan: 440 mm (17.5 in)
• Wing: 132.9–140.9 mm (5.23–5.55 in)
• Tail: 147.4–159.8 mm (5.80–6.29 in)
• Culmen: 20.2–23.9 mm (0.80–0.94 in)
• Tarsus: 21.1–24.1 mm (0.83–0.95 in)

Habitat

The Black-billed Cuckoo can be found in a variety of environments, from the edges of mature deciduous or mixed forests to younger-growth areas with dense shrubbery. They also frequent wetlands rich in alder and willow, as well as open spaces like abandoned farmlands and residential parks. A water source is typically nearby.

Distribution

This species breeds across much of the United States, east of the Rockies, and into southern Canada. During migration, it can be seen throughout Central America, eventually wintering in northwestern South America. It is occasionally spotted as a vagrant in western Europe and Greenland.

Behaviour

The Black-billed Cuckoo is known for its nomadic tendencies, especially post-migration, as it searches for optimal breeding grounds with abundant food sources. It is adept at concealing itself within its habitat, often remaining well-hidden.

Song & Calls

The call of the Black-billed Cuckoo consists of 2–5 sets of high-pitched, rapid "coo" notes, with a slight pause between each set. The young produce a buzzing sound resembling an insect and a low barking call when disturbed.

Breeding

Courtship involves the male presenting an insect to the female, who responds with tail flicking. The female typically lays 2–3 blue-green eggs, which are incubated for 10–13 days. Chicks leave the nest 7–9 days after hatching and adopt an erect posture to camouflage themselves from predators.

Similar Species

The Black-billed Cuckoo is often confused with the closely related Yellow-billed Cuckoo, but can be differentiated by its bill color and the red orbital ring in adults.

Diet and Feeding

The diet primarily consists of insects, particularly tent caterpillars, as well as snails, eggs of other birds, and berries. They have a unique adaptation that allows them to consume hairy caterpillars by shedding their stomach lining to expel indigestible hairs.

Conservation status

Classified as Least Concern, the Black-billed Cuckoo's population is nonetheless declining due to threats such as pesticide use, habitat loss, urbanization, and collisions with buildings during migration.