Yellow-billed Cuckoos are slender, long-tailed birds that manage to stay well hidden in deciduous woodlands. They usually sit stock still, even hunching their shoulders to conceal their crisp white underparts, as they hunt for large caterpillars. Bold white spots on the tail’s underside are often the most visible feature on a shaded perch. Fortunately, their drawn-out, knocking call is very distinctive. Yellow-billed Cuckoos are fairly common in the East but have become rare in the West in the last half-century.
Size & Shape
Yellow-billed Cuckoos are fairly large, long, and slim birds. The bill is almost as long as the head, thick and slightly downcurved. They have a flat head, thin body, and very long tail. Wings appear pointed and swept back in flight.
Color Pattern
Yellow-billed Cuckoos are warm brown above and clean whitish below. They have a blackish mask across the face and a yellow eyering. In flight, the outer part of the wings flash rufous. From below, the tail has wide white bands and narrower black ones. The bill is mostly yellow.
Habitat
They live mainly among the canopies of deciduous trees; look for them in woodland patches with gaps and clearings. In the West, this species is rare and restricted to the cottonwood-dominated forests that line larger rivers running through arid country.
Food
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.
Nesting
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.
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