The Mexican whip-poor-will (Antrostomus arizonae), is a medium-sized (22–27 cm) nightjar from the southwestern United States and Mexico. The whip-poor-will is more often heard within its range, but less often seen. It is named onomatopoeically after its song.
This bird used to be lumped with the eastern whip-poor-will. Each type has a different range and vocalizaton, the eggs have different coloration, and DNA sequencing shows enough differentiation, so it was determined enough evidence was available to separate the two types into different species.
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 woodlands of southwestern United States, and Mexico. 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.