The common poorwill (Phalaenoptilus nuttallii) is a nocturnal bird of the family Caprimulgidae, the nightjars. It is found from British Columbia and southeastern Alberta, through the western United States to northern Mexico. The bird's habitat is dry, open areas with grasses or shrubs, and even stony desert slopes with very little vegetation. Many northern birds migrate to winter within the breeding range in central and western Mexico, though some remain further north. Remarkably, the common poorwill is the only bird known to go into torpor for extended periods (weeks to months).