Wild Ideas: A mysterious bird calls in the night   

For years I’ve heard this strange, haunting animal sound at night in the forest surrounding my house. I was pretty sure it was a bird, but tracking down the species from its sound is much harder than flipping through the illustrations in a field guide. After listening to this sound more carefully all summer, I finally decided to take a shot at solving the mystery.

I thought about what birds are busy at night hunting for food, mating or both. The knocking and hollow, loud “kowp” sound I was hearing didn’t belong to any of our native owls. Nor did it sound like a member of the goatsucker family, which includes whip-poor-wills and nighthawks. So what was left?

When I don’t know where to start with identifying a bird, I often do what I did in this occasion — open one of my bird apps and scroll through the taxonomic orders, hoping a species name will click. In this case, I started with my Sibley Birds app. As I scrolled through the orders, I came to Cuculiformes, the cuckoos, roadrunners and anis.

Although Audubon shows a yellow-billed cuckoo preying on an adult eastern tiger swallowtail butterfly, the cuckoo’s favorite prey is the larvae of this and other Lepidoptera. By John James Audubon

This is an interesting group with which I have little first-hand experience, although I finally did check the greater roadrunner off my life list after my trip last fall to Death Valley National Park. Knowing this species is a desert bird that doesn’t range this far east, and no anis are generally seen here, I moved on to a genus in this order that does inhabit our area: the cuckoos.

Virginia has two cuckoos that are neotropical migrants, breeding here in warm season and wintering in South America: The yellow-billed cuckoo (Coccyzus americanus) and the black-billed cuckoo (C. erythropthalmus). Both have similar ranges here and like forest tracts with lots of water, but the black-billed prefers more extensive forest, which applies to the forest around my house. The property borders Shenandoah National Park, and the forest here extends well into the park. Having never seen either species in flesh, I managed to narrow down the identification to the yellow-billed through the sound, which I’d recorded and compared with that of both species.

The elegant yellow-billed cuckoo will sit still in trees when not gleaning insects off the leaves, making them hard to spot in the dappled light. Courtesy photo

Despite the yellow-billed’s being quite common, it is rarely seen. About the size of a blue jay, it has, like all cuckoos, a proportionately long tail and a long, thick bill that curves downward. Warm brown on top and white underneath, when not gleaning insects, it typically stays still in the forest canopy, blending into the dappled light there. Both native cuckoos have white spots on their tails, further camouflaging them in the canopy, but the yellow-billed’s spots are more defined.

“A graceful, elegant bird, calm and unperturbed, it slips quietly and rather furtively through its favorite tangles and flies easily from tree to tree,” as Edward Howe Forbush and John Bichard May describe the yellow-billed in their book “A Natural History of American Birds of Eastern and Central North America.” It is “far more heard than seen,” they add. “Indeed it would be rarely seen were it not for its rather loud unhurried notes.”

We Americans tend to be more familiar with Eurasian cuckoos than our own. These nonnative cousins are often featured in cartoons and on clocks, where they loudly proclaim their name. Our native cuckoos’ calls are more a rapid knocking along with the “kowp” sounds. Both natives make the latter call, but the more desultory “kowp” of the yellow-billed has fewer repetitions and more space between them. (Check the Macaulay Library for audio and video clips, along with still photos, of both species.)

Despite its being basically a diurnal bird, the yellow-billed is unusual in that it often makes these calls at any time, including the dead of night, much like the northern mocking bird, which is also diurnal. I most often hear the cuckoo’s calls from dusk to a few hours later. This species is also known to call at the sound of thunder, earning it two of its other common names: “thunder crow” and “rain crow.”

Along with nocturnal calling, another interesting thing about our cuckoos is their diet. With caterpillars at the top of the menu, they are the farmer’s friend. Although they nest in the canopy, the yellow-billed often hunts closer to the ground and has learned that orchards are loaded with these larvae.

While Audubon’s illustration of yellow-billed cuckoos (left) shows them in action, gleaning an eastern tiger swallowtail butterfly, this cuckoo blends into the forest canopy by sitting still and is heard more than seen (as in cropped photo at right by Melissa McMasters via Wikimedia). Courtesy image

“Wherever caterpillar outbreaks occur we hear the calls of the cuckoos,” Forbush writes. “There they stay; there they bring their newly fledged young; and the number of caterpillars they eat is incredible.” All About Birds reports that the yellow-billed can eat, in one foray, up to 100 of the spring-emerging tent caterpillars. And it will often delay its departure south when fall webworm caterpillars are abundant.

The cuckoos have the distinction among birds of being able to eat even hairy caterpillars, most of which are the larvae of moths. Some of these have hairs (setae) that are barbed and coated with a chemical that stings. But cuckoos have evolved to handle these nasty hairs, which fill up their stomach lining. When the stomach lining gets too filled with them, these birds merely shed the lining and develop a new one.

© 2017 Pam Owen

Interesting cuckoo reproductive facts

  • Eurasian cuckoos are notorious for laying their eggs in other birds’ nests, but Virginia’s native cuckoos only do this occasionally, typically in years when prey is so abundant that the cuckoos can produce more eggs than they can brood.
  • Yellow-billed cuckoos have one of the shortest nesting cycles of any bird species, according to All About Birds, with incubation through fledging taking as few as 17 days.
  • The nestlings of the yellow-billed cuckoo, as Forbush and May point out, have a “black, tough, leathery-appearing skin, and each feather as it grows is encased in a black, pointed sheath, giving the callow youngster the appearance of being clothed in quills like the ‘fretful porcupine.’” But, miraculously, within a few hours on the day of fledging, the sheaths “burst open” and “the young bird goes forth into the world properly clothed in a plumage resembling that of its parents.”
Pam Owen
About Pam Owen 344 Articles
Writer, editor, photographer, and passionate nature conservationist living in Rappahannock County, in the Blue Ridge Mountains of Virginia. Two favorite quotes: By E.O. Wilson, who coined the term "biodiversity," "Nature holds the key to our aesthetic, intellectual, cognitive and even spiritual satisfaction”; by Douglas Adams, “I love deadlines. I love the whooshing sound they make as they pass by.”