The Eastern Whip-poor-will, (Antrostomus vociferus), is a medium-sized (22–27 cm) nightjar bird from North and Central America. The whip-poor-will is commonly heard within its range, but less often seen because of its superior camouflage. It is named onomatopoeically after its song.
These medium-sized nightjars measure 22–27 cm (8.7–10.6 in) in length, span 45–50 cm (18–20 in) across the wings and weigh 42–69 g (1.5–2.4 oz). Among standard measurements, the wing chord is 14.7 to 16.9 cm (5.8 to 6.7 in), the tail is 10.5 to 12.8 cm (4.1 to 5.0 in), the bill is 1 to 1.4 cm (0.39 to 0.55 in) and the tarsus is 1.5 to 1.8 cm (0.59 to 0.71 in). Adults have mottled plumage: the upperparts are grey, black and brown; the lower parts are grey and black. They have a very short bill and a black throat. Males have a white patch below the throat and white tips on the outer tail feathers; in the female, these parts are light brown.
Their habitat is deciduous or mixed woods across western, central and southeastern Canada, eastern United States, and Central America. Northern birds migrate to the southeastern United States and south to Central America. Central American races are largely resident. These birds forage at night, catching insects in flight, and normally sleep during the day. Whip-poor-wills nest on the ground, in shaded locations among dead leaves, and usually lay two eggs at a time. The bird will commonly remain on the nest unless almost stepped upon.
The eastern whip-poor-will is becoming locally rare. Several reasons for the decline are proposed, such as habitat destruction, predation by feral cats and dogs, and poisoning by insecticides, but the actual causes remain elusive. Even with local populations endangered, the species as a whole is not considered globally threatened due to its large range. In the northern lower Michigan (USA) Huron National Forest, the common knowledge of area sportsmen and conservation entities is the population of the eastern whip-poor-will, and most other small ground birds and animals, fluctuates in response to the population of coyotes. The populations average an approximately three year cycle, with the bird populations being higher in years of lower coyote populations and as the coyote population climbs, the bird population drops to the point the coyotes run low on viable food sources. At that point the coyote population collapses and the bird and other small ground animal populations re-surge, only to repeat the process again. 2013 has seen a great increase in whip-poor-wills, woodcock and partridge in this area of Michigan, with a noted reduction in coyote activity.
The whip-poor-will has been split into two species. Eastern populations are now referred to as the eastern whip-poor-will. The disjunct population in southwestern United States and Mexico is now referred to as the Mexican Whip-poor-will, Caprimulgus arizonae. The two species having different ranges and vocalizations, the eggs having different coloration, and DNA sequencing showing enough differentiation, it was determined enough evidence was available to separate the two types into different species.
Due to its haunting, ethereal song, the eastern whip-poor-will is the topic of numerous legends. One New England legend says the whip-poor-will can sense a soul departing, and can capture it as it flees. This is used as a plot device in H. P. Lovecraft's story The Dunwich Horror. Lovecraft based this idea on information of local legends given to him by Edith Miniter of North Wilbraham, Massachusetts when he visited her in 1928. This is likely related to an earlier Native American and general American folk belief that the singing of the birds is a death omen. This is also referred by Whip-poor-will, a short story by James Thurber, in which the constant nighttime singing of a whip-poor-will results in maddening insomnia of the protagonist Mr Kinstrey who eventually loses his mind and kills everyone in his house, including himself. The bird also features, however, in The Runaway Slave at Pilgrim's Point, a poem by the English poet Elizabeth Barrett Browning, in which the outcast speaker asks: "Could the whip-poor-will or the cat of the glen/Look into my eyes and be bold?" 
It is also frequently used as an auditory symbol of rural America, as in Washington Irving's story The Legend of Sleepy Hollow, or as a plot device. For example, William Faulkner's short story, "Barn Burning", makes several mentions of whip-poor-wills, e.g.: "and then he found that he had been asleep because he knew it was almost dawn, the night almost over. He could tell that from the whip-poor-wills. They were everywhere now among the dark trees below him, constant and inflectioned and ceaseless, so that, as the instant for giving over to the day birds drew nearer and nearer, there was no interval at all between them." 
"The Mountain Whippoorwill" is a poem written by Stephen Vincent Benet about a fiddling contest, won by Hillbilly Jim, who refers to his fiddle as a whip-poor-will and identifies the bird with the lonely and poor but vibrant life of the mountain people. American poet Robert Frost described the sound of a whip-poor-will in the fourth stanza of his 1915 poem "Ghost House". This is notable in Frost's use of assonance, in "The whippoorwill is coming to shout / And hush and cluck and flutter about."
In the 1934 Frank Capra film It Happened One Night, before Clark Gable's character Peter Warne reveals his name to Ellie Andrews (Claudette Colbert), he famously says to her: "I am the whip-poor-will that cries in the night".
"Whippoorwill" is a song from Annuals 2013 album "Time Stamp". It makes a mention of the bird with the lines "A cold dead night, after a windswept day the fire burns high. But I’m just listening to the whippoorwills cry. Oh how it carries so fine. I’ll bet it floats miles straight through your window."
- Holyoak, D.T. (2001): Nightjars and their Allies: the Caprimulgiformes. Oxford University Press, Oxford, New York. ISBN 0-19-854987-3.
- For example, Henninger (1906) combines the old scientific name of C. carolinensis with the common name "whip-poor-will". As C. carolinensis does not occur in the area discussed, he obviously refers to C. vociferus. In other cases, the specific identity of birds may not be determinable.
- MWP (2008)
- BLI (2004)
- Chesser, R. T., R. C. Banks, F. K. Barker, C. Cicero, J. L. Dunn, A. W. Kratter, I. J. Lovette, P. C. Rasmussen, J. V. Remsen, Jr, J. D. Rising , D. F. Stotz, and K. Winker. 2010. Fifty-first supplement to the American Ornithologists’ Union Check-list of North American Birds. Auk 127(3):726-744.
- Encyclopedia of Superstitions, p. 716.
- http://classiclit.about.com/library/bl-etexts/ebbrowning/bl-ebbrown-runaway-1.htm. Lines 55-56.
- Faulkner, William. "Barn Burning". www.rajuabju.com. Retrieved 1 May 2011.
- IMDb Quotes: It Happened One Night.
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