Phalaenoptilus nuttallii (Audubon 1844)

A small nightjar of the arid West, the Common Poorwill is the smallest member of its family in North America. It is one of the few birds known to hibernate during the winter. The Common Poorwill can slow its metabolic rate and drop its body temperature, going into a hibernation-like state known as "torpor." In periods of cold weather, a poorwill may stay in torpor for several weeks. Although probably not true hibernation, topor allows the bird to go long periods of time without food and can help it survive cold spells when its insect prey would not be active. Common Poorwills in the laboratory readily enter torpor when deprived of food.