Despite their value to gardeners, fruit growers and arborists, cuckoos are unknown to most Americans; only birders and naturalists are familiar with these jay-sized, curve-billed, long-tailed summer residents. Yet, their appetite for hairy caterpillars (including tent caterpillars), eschewed by most birds, helps to protect natural and agricultural plants alike.
Yellow-billed and black-billed cuckoos are fairly common summer residents throughout most of the U.S. and southern Canada; the black bills are more common in the north, while the yellow bills dominate across the southern States. A third species, the mangrove cuckoo, is found along the coastal areas of southern Florida. All three of these cuckoos favor dense foliage along streams and inlets and are more often heard than seen; their calls, distinct for each species, are characterized by repetitive series of monotone notes.
In my experience, black-billed and yellow-billed cuckoos are most often encountered in residential areas during September or early October. Leaving their summer haunts, they begin to roam about open woodlands, feasting on a variety of caterpillars and preparing for their journey to the south; they will winter in South America.
