I heard my first whippoorwill nearly a month ago, after going my whole life without hearing one (that I was aware of). Yet I immediately recognized his unmistakable song – WHIP-oor-WILL, WHIP-oor-WILL, WHIP-oor-WILL – on and on into the dwindling twilight.
Science-fiction writer August Derleth based an entire story, “The Whippoorwills in the Hills,” on the mysterious nature of this elusive little bird with an outsized mouth. “Never once did their calling cease,” he writes of the birds, which come to symbolize an ominous presence throughout the story. Multitudes of fanciful whippoorwills lurk near the narrator’s house, driving him mad with their cacophony. But we should be so lucky. Recollections from old-timers say that the whippoorwill’s refrain was a common and welcome choral event during early-twentieth-century evenings. Yet by all modern anecdotal and research accounts, this summery song is becoming rarer.
Whippoorwills prefer forests with little or no underbrush, which are being lost across much of their breeding range (most of the eastern U.S.). Losses of forest to development, agricultural crops, and grazing have all contributed to the decline of woods these birds prefer: dry deciduous or mixed deciduous-coniferous forests that absolutely must have an open understory – piney woods, barrens, and overgrown fields are best, but not dark, mature, unbroken expanses. The key elements are shade, proximity to open areas for foraging, and sparse ground cover. The birds thrive in patches of forest that are fairly extensive – islands of woods in a sea of agricultural fields just won’t do – but there must be some open habitat nearby in which to forage.
Complicating matters is the fact that whippoorwills are extremely difficult to find and observe. Ornithologist Winsor Tyler said that the whippoorwill lives “on the border of invisibility.” According to The Birds of North America, “More frequently heard than seen, the Whip-poor-will remains an elusive species even for seasoned field ornithologists.” We know where they breed from the territorial calling of the males, but few nests have been found. Eggs and young that blend right into the forest floor, a nocturnal lifestyle, and large territories add to the whippoorwill’s elusiveness. Perhaps their mysterious nature led Derleth to feature whippoorwills as the agent of malice in his story – and you can hardly blame him, because if you take a closer look at them, the oddities of whippoorwills become even more intriguing.
With a large flat head and big eyes, whippoorwills sport a tiny, mustached bill that can open wide enough to catch and swallow insects up to 2 inches long. The whippoorwill is in the family called goatsuckers – really any bird with a weak, bristled bill. Indeed, the bird’s Latin name – Caprimulgus vociferus – can be loosely translated as “milk goat powerful voice.” While the bristles actually serve to help suck insects into the mouth, a myth that goes back at least to Aristotle’s time says that the massive gape of the birds enabled them to suck the milk of goats. Adding to their vampirish appeal, whippoorwill chicks hatch in conjunction with the full moon – though this can be explained by the increased visibility of insects by moonlight.
Besides losing habitat, these funny birds are vulnerable on other flanks. Because they nest on the ground, whippoorwills are at greater risk than some other birds of being caught by predators, including domestic cats. They are also more likely to be hit by cars if they nest or hunt near highways (watch for their red eye-shine to give them away). Researchers have further hypothesized that whippoorwills are susceptible to industrial pollution and pesticide use and, like any predator, the loss of their favorite prey item – members of the giant silk moth family, including cecropia and luna moths.
According to Steve Faccio at the Vermont Institute of Natural Science, these moths are declining in numbers, perhaps as a result of Bacillus thuringiensis (Bt), a “natural” insecticide used against gypsy moths and other pests that can affect innocent moths, too. The Animal Plant Health Inspection Service lists Bt as the primary eradication tool for gypsy moths – although new, natural control methods are currently under development. Additionally, a non-native parasitic fly targets silk moth caterpillars. Without these easy meals, whippoorwills have to spend more time foraging and sometimes lose out to more efficient competitors – whippoorwills are only able to hunt by sight alone.
Whippoorwills are being hit hard from all sides, but still they persist here and there in our forests. “I have only heard one from my house in Strafford,” writes Faccio, “and I’ll never forget it, I could hear whippoorwill, snipe, woodcock, peepers, toads, and American bittern all singing at the same time, a regular symphony.” If you venture outside on a summer night, listen and maybe you’ll be rewarded with the enchanting melody of the whippoorwills in the hills.