Coccyzus americanus
yellow-billed cuckoo

Yellow-billed cuckoos are found in the Nearctic and Neotropical regions. They breed throughout eastern North America, in southeast Canada, northern Mexico and the Greater Antilles. They winter primarily in South America (Peru, Bolivia and northern Argentina). (Hughes, 1999)

Yellow-billed cuckoos prefer open woodlands with clearings and a dense shrub layer. They are often found in woodlands near streams, rivers or lakes. In North America, their preferred habitats include abandoned farmland, old fruit orchards, successional shrubland and dense thickets. In winter, yellow-billed cuckoos can be found in tropical habitats with similar structure, such as scrub forest and mangroves. (Hughes, 1999)

Yellow-billed cuckoos are medium birds (26 to 30 cm long; 55 to 65 g) with long tails. They have uniform grayish-brown plumage on their head and back, and dull white underparts. Their tails are long with two rows of four to six large white circles on the underside. The bill of yellow-billed cuckoos is short to medium in length and curved downward with a black upper mandible and a yellow or orange lower mandible. Yellow-billed cuckoos have zygodactylous feet, meaning that of the four toes, the middle two point forward and the outer two point backward. (Parker)

Female yellow-billed cuckoos are slightly larger than males. Juveniles are similar in appearance to adults, but have a less distinct undertail pattern, and have cinnamon brown wing coverts.

There are two recognized subspecies of Coccyzus americanus; Coccyzus americanus americanus (the eastern version) and its western counterpart, Coccyzus americanus occidentalis. These two subspecies are differentiated by tail, wing and bill length. (Hughes, 1999)

Yellow-billed cuckoos are probably monogamous, though their breeding system has not been well studied. Breeding pairs form in May or June, and pairs may visit prospective nest sites together before choosing a location. Males may attempt to procure or keep a mate by offering sticks and other nest materials to their mate as well as feeding them (Eaton, Erlich et al). (Hughes, 1999)

Yellow-billed cuckoos begin breeding in mid- to late-May. Most populations breed once per year, though some eastern populations may raise two broods in one breeding season. The male and female build the nest, which is made of twigs, lined with roots and dried leaves, and rimmed with pine needles. The female may begin laying eggs before nest construction is complete. She lays 1 to 5 (usually 2 or 3) light blue eggs, and begins incubating after the first egg is laid. Incubation is done by both parents, and lasts 9 to 11 days.

Yellow-billed cuckoo chicks are altricial at hatching, and are brooded often by the parents for the first week or so. Both parents feed the chicks, which begin to leave the nest 7 to 9 days after hatching. They begin to fly about 21 days after hatching. Soon thereafter they leave the nest for good. The male will usually take care of the first fledgling, and the female will care for the rest (Ehrlich et al.). There is little information available on when yellow-billed cuckoo chicks become independent from their parents. Most yellow-billed cuckoos begin breeding at age 1.

Some yellow-billed cuckoos may parasitize other birds by laying eggs in the nest of other parents. They may lay eggs in the nest of other yellow-billed cuckoos, or in the nests of other bird species, including black-billed cuckoos, American robins, gray catbirds and wood thrushes. (Hughes, 1999)

Male and female yellow-billed cuckoos incubate eggs, brood and feed chicks and protect the nest from predators. They also keep the nest clean by removing the fecal sacs of the chicks. After chicks have left the nest, the parents continue to feed them until they are able to care for themselves. The length of this period is unknown. (Hughes, 1999)

There is little information available about the lifespan and survivorship of yellow-billed cuckoos. The oldest re-captured banded yellow-billed cuckoos were 4 years old at re-capture. (Hughes, 1999)

Yellow-billed cuckoos are solitary or live in pairs during the breeding season. They may be territorial, but this aspect of their behavior is not well understood. Yellow-billed cuckoos are fully migratory. They migrate at night in small groups or large flocks. Outside of migration, yellow-billed cuckoos are generally diurnal. (Hughes, 1999)

Yellow-billed cuckoos primarily use vocalizations to communicate. They are generally silent birds during the winter and migration, but vocalize regularly during the early breeding season before the chicks fledge. These birds are able to make at least 6 vocal sounds, which are used for a wide variety of social situations. Few physical displays have been noted in this species. (Hughes, 1999)

Yellow-billed cuckoos primarily eat large insects including caterpillars (order Lepidoptera), katydids, cicadas (family Cicadidae), grasshoppers and crickets (order Orthoptera). They also occasionally eat bird eggs, snails, small vertebrates such as frogs (Order Anura) and lizards (suborder Sauria) and some fruits and seeds. Parents feed their chicks regurgitated insects (Ehrlich et al.).

Adult yellow-billed cuckoos are killed by raptors, including Aplomado falcons (Falco femoralis) and red-shouldered hawks (Buteo lineatus). Remains of adults have also been found in the stomach of a tiger shark (Galeocerdo cuvier). Nestlings and eggs are vulnerable to predation by snakes such as the black racer (Coluber constrictor), small mammals such as eastern chipmunks (Tamias striatus), and birds such as blue jays (Cyanocitta cristata) and common grackles (Quiscalus quiscula).

When threatened by a predator, yellow-billed cuckoos often hide themselves among vegetation and remain motionless. If a nest is threatened, parents will either attack the predator or try to lure the predator away from the nest by flying away and performing a distracting display and vocalizations. (Hughes, 1999)

Yellow-billed cuckoos affect the populations of the species they prey on. They are also host to internal and external parasites.

Yellow-billed cuckoos are also nest parasites, and may affect the reproductive success of species that they parasitize. Some yellow-billed cuckoos parasitize other birds by laying eggs in their nests. They may lay eggs in the nest of other yellow-billed cuckoos, or in the nests of other bird species, including black-billed cuckoos, American robins, gray catbirds and wood thrushes. If the parasitized parents raise the foreign young, their own chicks may be less likely to survive or flourish. (Hughes, 1999)

Yellow-billed cuckoos may help to control populations of pest insects.

There are no known adverse affects of yellow-billed cuckoos on humans.

Yellow-billed cuckoos are protected under the U.S. Migratory Bird Act. They are considered threatened or endangered in several states, and are a candidate for protection under the U.S. Endangered Species Act. Yellow-billed cuckoos are common in parts of their range, but populations have been declining in recent years throughout much of the range. This decline is most likely due to habitat loss and fragmentation. Other threats to cuckoo populations include poisoning from pesticides and other environmental contaminants and collision with towers and tall buildings during their nocturnal migration. (Hughes, 1999)