Yellow-billed Cuckoo

The Yellow-billed Cuckoo is a long, slim bird with smooth grayish-brown upperparts, clean white underparts, and a long tail boldly marked below with large white spots against black. Its most distinctive feature is the bill: mostly yellow on the lower mandible, giving the species its name.

Despite its size, the Yellow-billed Cuckoo is remarkably hard to see, moving quietly and deliberately through dense leafy canopy. It is best known to most people not by sight but by its unusual, hollow, knocking call, and by an old folk belief that it calls ahead of rain — earning it the nickname "rain crow."

Key Field Marks

• Slim, long-tailed silhouette with smooth grayish-brown upperparts and clean white underparts
• Yellow lower mandible contrasting with a dark upper bill
• Rufous-cinnamon patch in the primary flight feathers, visible in flight
• Long tail with bold white spots on the underside, arranged like a row of dots

Similar Species

The Black-billed Cuckoo is very similar in shape and size but has an all-dark bill, a red eye-ring, and lacks the rufous wing patch and bold tail spotting (its tail spots are smaller and grayer). Mourning Doves are sometimes mistaken for cuckoos in flight but have a different, more direct flight style and no rufous wing patch.

Yellow-billed Cuckoos favor dense deciduous woodland with a thick understory, especially riparian corridors lined with willows and cottonwoods, as well as overgrown orchards, hedgerows, and shrubby second growth. They are widespread breeders across the eastern and central United States, with a smaller, now-fragmented population in the West tied closely to large river cottonwood-willow forests.

The species is a long-distance migrant, wintering in South America, and arrives on its breeding grounds later than most songbirds, often not until late May or June, timed to coincide with outbreaks of caterpillars.

Yellow-billed Cuckoos are famous for their fondness for hairy caterpillars, including tent caterpillars and fall webworms that most birds avoid, and they are also effective at consuming large numbers of cicadas during periodic emergences. They move slowly and deliberately along branches, unlike the quick hopping of many songbirds, often freezing motionless when disturbed.

The call is a distinctive, hollow, knocking "ka-ka-ka-ka-kow-kow-kowlp-kowlp," slowing and dropping in pitch toward the end. Nests are loose, flimsy twig platforms placed in dense foliage, and the species is known for having one of the shortest incubation periods of any bird, sometimes hatching in as few as nine to eleven days.