- 10.2–11.8 in
- 15–16.9 in
- 1.9–2.3 oz
- Longer, but slighter, than American Kestrel; about the size of a Blue Jay or Western Scrub-Jay.
- Coulicou à bec jaune (French)
- Cuclillo pico amarillo, Platero piquiamarillo (Spanish)
- Yellow-billed Cuckoos are among the few bird species able to eat hairy caterpillars. In the East they eat large numbers of tent caterpillars—as many as 100 in one sitting.
- Yellow-Billed Cuckoos don’t lay their eggs all at once: the period between one egg to the next can stretch to as long as five days. This “asynchronous” egg laying means the oldest chick can be close to leaving the nest when the youngest is just hatching. When food is in short supply the male may remove the youngest bird from the nest, though unlike their relative the Greater Roadrunner, they don’t feed them to the older siblings.
- If threatened, nesting pairs of Yellow-billed Cuckoos will react with a “distraction display” designed to lure potential predators away from the nest site. While one bird remains on the nest, the other hops to a visible perch, opening its wings and pumping its tail up and down. In open nesting areas, a bird flushed from the nest flutters away in a slow, wavering flight, flashing its rufous wing patches and white tail spots.
- Yellow-Billed Cuckoos have a primal-sounding, croaking call that they often give in response to loud noises. Their tendency to call at the sound of thunder has led to their colloquial name, the “rain crow.”
- Yellow-billed Cuckoos sometimes lay their eggs in other birds’ nests—although they don’t do this nearly as often as the Common Cuckoo of Eurasia, which made the behavior famous. When outbreaks of cicadas, tent caterpillars, gypsy moths, and other prey create an abundant food supply, Yellow-billed Cuckoos sometimes lay eggs in nests of other cuckoos as well as in those of American Robins, Gray Catbirds, and Wood Thrushes.
- Both parents build the nest, incubate the eggs, and brood the nestlings. They incubate and brood equally during the day, but the male takes the night shift. The male brings nest material every time he comes to the nest to take his turn. The female usually takes the offering and works it into the nest.
- Yellow-billed Cuckoos have one of the shortest nesting cycles of any bird species. From the start of incubation to fledging can take as little as 17 days. Although born naked, the young birds develop quickly; within a week of hatching the chicks are fully feathered and ready to leave the nest.
- The oldest known Yellow-billed Cuckoo was at least 5 years old when it was found in Tennessee. It had been banded in Florida.
Yellow-billed Cuckoos use wooded habitat with dense cover and water nearby, including woodlands with low, scrubby, vegetation, overgrown orchards, abandoned farmland, and dense thickets along streams and marshes. In the Midwest, look for cuckoos in shrublands of mixed willow and dogwood, and in dense stands of small trees such as American elm. In the Southwest, Yellow-Billed Cuckoos are rare breeders in riparian woodlands of willows, cottonwoods and dense stands of mesquite to breed.
Caterpillars top the list of Yellow-Billed Cuckoo prey: individual cuckoos eat thousands of caterpillars per season. On the East coast, periodic outbreaks of tent caterpillars draw cuckoos to the tentlike webs, where they may eat as many as 100 caterpillars at a sitting. Fall webworms and the larvae of gypsy, brown-tailed, and white-marked tussock moths are also part of the cuckoo’s lepidopteran diet, often supplemented with beetles, ants, and spiders. They also take advantage of the annual outbreaks of cicadas, katydids, and crickets, and will hop to the ground to chase frogs and lizards. In summer and fall, cuckoos forage on small wild fruits, including elderberries, blackberries and wild grapes. In winter, fruit and seeds become a larger part of the diet.
- Clutch Size
- 1–5 eggs
- Number of Broods
- 1-2 broods
- Egg Length
- 1.1–1.4 in
- Egg Width
- 0.8–1 in
- Incubation Period
- 9–11 days
- Nestling Period
- 8 days
- Egg Description
- Smooth, unmarked, pale bluish-green fading to light greenish yellow.
- Condition at Hatching
- Chicks are born naked but are alert and active within 10 minutes of hatching; they become partly covered in pin feathers within 24 hours, with one or both eyes open.
The male and female Yellow-Billed Cuckoo build a loose stick nest together, using twigs collected from the ground or snapped from nearby trees and shrubs. They construct a flat, oblong platform reaching up to 5 inches deep and 8 inches in diameter. The pair may line the nest sparingly with strips of bark or dried leaves. The finished nest cup is about 5 inches across and 1.5 inches deep. The male sometimes continues bringing in nest materials after incubation has begun.
Pairs may visit prospective nest sites multiple times before building a nest together. Nest heights can range from 3 feet to as much as 90 feet off the ground, with the nest placed on a horizontal branch or in the fork of a tree or large shrub. In the central and eastern U.S., Yellow-billed Cuckoos nest in oaks, beech, hawthorn, and ash. Pine, juniper, and fir are used less frequently. In the West, nests are often placed in willows along streams and rivers, with nearby cottonwoods serving as foraging sites.
Yellow-Billed Cuckoos are patient feeders, sitting motionless on hidden perches, often with shoulders hunched to disguise their white chest and belly as they wait for prey to move. They glean insects from leaves and may hop to the ground to chase lizards, frogs and grasshoppers, or sally out like a flycatcher to grab a flying insect. Caterpillars are a favorite prey item: the cuckoo will roll a caterpillar back and forth through its bill, perhaps to try and strip off some of the spiny hairs. Cuckoos may respond to available food supplies rather than a set season to begin breeding. A receptive female perches with its head up, pumping its tail slowly up and down in a 180-degree arc. Just prior to mating, the male Yellow-Billed Cuckoo snaps off a short twig that he presents to the female as he perches on her back and leans over her shoulder. Both birds then grasp the twig as they copulate. When they do leave a sheltered perch, the Yellow-Billed Cuckoo’s flight is swift and direct, with deep beats of their long pointed wings.
Yellow-billed Cuckoo populations declined by over 1.5% per year between 1966 and 2014, resulting in a cumulative decline of 53%, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at about 9 million, with 84% breeding in the U.S., and 10% spending some part of the year in Mexico. They score a 12 out of 20 on the Continental Concern Score, and the 2014 State of the Birds Report lists them as a Common Bird in Steep Decline. In the West, much of the Yellow-Billed Cuckoo’s riparian habitat has been converted to farmland and housing, leading to significant population declines and the possible extirpation of cuckoos from British Columbia, Washington, Oregon, and Nevada. Once common in the California’s Central Valley, coastal valleys, and riparian habitats east of the Sierra Nevada, habitat loss now constrains the California breeding population to small numbers of birds along the Kern, Sacramento, Feather, and Lower Colorado Rivers. The western population of Yellow-billed Cuckoos is a candidate for federal endangered status. Sites replanted with riparian vegetation in southern California supported breeding birds within three years, demonstrating the potential for habitat restoration. As long-distance, nocturnal migrants, Yellow-Billed Cuckoos are vulnerable to collisions with tall buildings, cell towers, radio antennas, wind turbines, and other structures.
- Hughes, Janice M. 1999. Yellow-Billed Cuckoo (Coccyzus americanus). In The Birds of North America Online, No. 418 (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca, New York.
- Laymon, S. A. 1998. Yellow-billed Cuckoo (Coccycus americanus). In The Riparian Bird Conservation Plan: a strategy for reversing the decline of riparian-associated birds in California. California Partners in Flight.
- Laymon, S. A. 2001. Cuckoos, roadrunners, and anis. In The Sibley Guide to Bird Life and Behavior, C. Elphic, J. B. Dunning, Jr., and D. A. Sibley (eds.). A. A. Knopf, New York.
- North American Bird Conservation Initiative, U.S. Committee. 2014. State of the Birds 2014 Report. U.S. Department of Interior, Washington, DC.
- Partners in Flight. 2012. Species assessment database.
- USGS Patuxent Wildlife Research Center. 2015. Longevity records of North American Birds.
- USGS Patuxent Wildlife Research Center. 2014. North American Breeding Bird Survey 1966–2014 Analysis.
Long-distance migrant. Yellow-Billed Cuckoos migrate to South America for the winter. East coast birds travel via Central America and the West Indies; western birds likely move down the western slope of Mexico and through Central America.
Find This Bird
Yellow-billed Cuckoos are fairly easy to hear but hard to spot. In summer, start by looking in areas of deciduous forest for infestations of tent caterpillars, as well as outbreaks of cicadas or other large arthropods. Listen for the species’ distinctive, knocking call, which can be given at any time, night or day. Later in summer, listen more for their dove-like cooing, as they give their knocking call much less frequently. The species is virtually silent by day during migration, so watch for their distinctive long, slim shape and rapid and fluid wingbeats as they cross over open patches below treetop level on their way from one woodlot to another. In fall, areas with fall webworm infestations often support Yellow-billed Cuckoos.