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 (8.7–11 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 Whippoorwill, 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 Whippoorwills, 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, MA 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 whippoorwill 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 whippoorwills, 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 whippoorwills. 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 the title of a poem written by Stephen Vincent Benet about a fiddling contest, won by Hillbilly Jim, who refers to his fiddle as a whippoorwill 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 whippoorwill 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."
- The Czech composer Bohuslav Martinu when resident in New England, imitated the Whip-poor-will's song in his Sonata for Flute and Piano (1945) H. 306
Whip-poor-wills are mentioned in numerous notable songs.
- "Alone & Forsaken", by Hank Williams, Sr. -
- "The roses have faded, there's frost at my door /
- The birds in the morning don't sing anymore
- The grass in the valley is starting to die
- And out in the darkness the whippoorwills cry."
- "As Above, So Below", by Klaxons -
- "A whiporwhil will in flight, turns east towards westphalia."
- "Away on the Mountain" by Jimmie Rodgers.
- "where the whippoorwill's sing me to sleep at night, and the eagle roosts on the rocks of spontane"
- "Brand New Angel", performed by Jeff Bridges on the 2009 soundtrack Crazy Heart
- "By a Waterfall, composed by Sammy Fain with lyrics by Irving Kahal as featured in the film Footlight Parade.
- "A Cockeyed Optimist", from the musical South Pacific written by Rodgers and Hammerstein
- "Call of the Whip-Poor-Will", by the Stapleton Brothers
- "Deeper Than The Holler", by Randy Travis
- "Satisfied 'n Tickled Too", by Mississippi John Hurt
- "I'm So Lonesome I Could Cry", by Hank Williams
- "Hear that lonesome whip-poor-will /
- He sounds too blue to fly."
- "I Got A Name" by Jim Croce
- "I Still Like Bologna", by Alan Jackson
- "If the World Had a Front Porch", by Tracy Lawrence on his 1994 album I See it Now
- "Kennesaw Line", by Don Oja-Dunaway, sung by Claire Lynch and the Front Porch String Band, references the legend of the whippoorwill as an omen of death (see Sam Watkins).
- "Little Bird, Little Bird", by Elizabeth Mitchell, mentioned the whippoorwill alongside various other birds
- "The Littlest Birds", by The Be Good Tanyas
- "Lonesome", a song by Dr. Dog from their 2012 album Be The Void
- Described by the band as a response to Williams's "I'm So Lonesome I Could Cry":
- "I had my fill of the whippoorwill /
- When he broke into song I shot him."
- "Magnolia", a song by J J Cale from his 1971 album Naturally.
- "Magpie to the Morning", by Neko Case
- "Midnight in Montgomery", by Alan Jackson
- "Mockingbird Hill", by Patti Page and Burl Ives and the group Les Paul and Mary Ford.
- "Moliannwn" Traditional Welsh
- "Mr. Ting-a-ling (Steel Guitar Man)" by George Morgan
- "My Blue Heaven", by Walter Donaldson/George A. Whiting,
- "My Blue Ridge Mountain Boy", by Dolly Parton
- "My Home Among the Hills", by E.W. James Jr
- "My Rifle, My Pony and Me", sung by Dean Martin and Ricky Nelson from the film Rio Bravo
- "Peace a Dime", composed by Charles Brooks in 2005
- "Philadelphia Freedom", a 1975 number-one hit by Elton John
- "Sad, Sad Song", by M. Ward
- "So Sang the Whippoorwill", by Run Boy Run
- "So Says the Whippoorwill", by Richard Shindell
- "Songs About Texas", by Pat Green
- "Sounds So Good", by Ashton Shepherd
- "Sunday In the South", by Shenandoah
- "Talking to the Moon" by Don Henley, from his 1982 album I Can't Stand Still
- "Tammy" by Debbie Reynolds
- "That Sunday, That Summer", by Nat King Cole
- "Trouble Won't Last Always" by Glossary (2011)
- "Up on the Ridge" (2010) by Dierks Bentley
- "The Verdant Mile", by contemporary folk legend Tracy Grammer
- "Whip-poor-will", by Magnolia Electric Co.
- "Whiporwill", by the Ozark Mountain Daredevils
- "Whiporwill", by Storyhill
- "The Whippoorwill", by Walela
- "Nothing But A Whiporwill", by Blue Highway
- "Whiporwill" by Doug Burr on the album On Promenade
- "Why Don't You Just Go Home" by Greg Brown on the album "Slant 6 Mind"
- "Daniel and The Sacred Harp" by The Band on the album Stage Fright
- "Bed of my Chevy" by Justin Moore
- "Hear the Whippoorwill Sing" by Roger D. Cranford
- "Painted Bird" by Siouxsie and the Banshees on 'A Kiss in the Dreamhouse'
- "Willows and Whippoorwills" by Caïna on 'Temporary Antennae'
- "Speed of the Whippoorwill" by Chatham County Line on the album "Speed of the Whippoorwill"
- "Jesse Like Birds" by Carrie Elkin on 'Call it My Garden'.
- "Country Is" by Tom T Hall on the album 'Country Is' 1975.
- "Bandit" by Birdcloud on their self-titled 2011 EP.
- "Title Track" by Okkervil River on the album "The Stage Names".
- "The Whipoorwill" by Blackberry Smoke on the album The Whipoorwill 
- "Whippoorwill" by Annuals on the album 'Time Stamp'.
- "Gus: The Polar Bear from Central Park" from In Between Evolution by The Tragically Hip
Nearby Lion's Head, Ontario, Whippoorwill Road has been named due to the bird's common distribution in that region. Whippoorwill Bay is also named near that location, as part of Isthmus Bay, closed by the cliffs named 'White Bluff' and Lion's Head. Also, in the area of the small town of Northern Michigan, USA, Glennie, is a subdivision called Sunny Lake, where the road into the subdivision is named Whippoorwill Drive, because of the number of Whippoorwills in that area. .
- 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".
- Numerous episodes of the TV series The Waltons.
- 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.
- See sheet music facsimile at www.freehandmusic.com/sheet-music/my-blue-heaven-111894
- IMDb Quotes: It Happened One Night.
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