Eastern whip-poor-will

The eastern whip-poor-will (Antrostomus vociferus; also called "whip-o-will", "whip o' will", etc.) is a medium-sized (22–27 cm or 8.7–10.6 in) bird within the nightjar family, Caprimulgidae, from North America. The whip-poor-will is commonly heard within its range, but less often seen because of its camouflage. It is named onomatopoeically after its song.

This medium-sized nightjar measures 22–27 cm (8+1⁄2–10+1⁄2 in) in length, spans 45–50 cm (17+1⁄2–19+1⁄2 in) across the wings and weighs 42–69 g (1+1⁄2–2+7⁄16 oz). Further standard measurements are a wing chord of 14.7 to 16.9 cm (5+13⁄16 to 6+5⁄8 in), a tail of 10.5 to 12.8 cm (4+1⁄8 to 5+1⁄16 in), a bill of 1 to 1.4 cm (3⁄8 to 9⁄16 in) and a tarsus of 1.5 to 1.8 cm (9⁄16 to 11⁄16 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.

This bird is sometimes confused with the related chuck-will's-widow (Antrostomus carolinensis) which has a similar but lower-pitched and slower call.

Eastern whip-poor-wills breed in deciduous or mixed woods across central and southeastern Canada and the eastern United States, and migrate to the southeastern United States and to eastern Mexico and Central America for the winter. These birds forage at night, catching insects in flight, and normally sleep during the day. Eastern 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.^{[citation needed]}

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, Antrostomus arizonae. The two populations were split based on range, different vocalizations, different egg coloration, and DNA sequencing showing differentiation.

The diet of an Eastern whip-poor-will mostly consists of insects, especially moths, also beetles, mosquitoes, and many others.

The eastern whip-poor-will is currently in decline, though they remain fairly common. In 2017, the eastern whip-poor-will was uplisted from least concern to near threatened on the IUCN Red List on the basis of citizen science observations demonstrating a decline in populations of the eastern whip-poor-will by over 60% between 1970 and 2014. Several reasons for the decline are proposed, such as loss of early successional forest habitat related to fire suppression and habitat destruction, predation by feral cats and dogs, and poisoning by insecticides, but the actual causes remain elusive. Pesticides and intensified agriculture have led to declines in the flying insect populations that the eastern whip-poor-will depends on. BirdLife International has stated that initiatives like the Conservation Reserve Program will be crucial in conserving the species and reversing its decline.

Due to its song, the eastern whip-poor-will is the topic of numerous legends. A 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 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?"