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. The common poorwill is the only bird known to go into torpor for extended periods (weeks to months). This happens on the southern edge of its range in the United States, where it spends much of the winter inactive, concealed in piles of rocks. Such an extended period of torpor is close to a state of hibernation and is not known among other birds.
Cr
CrepuscularCrepuscular animals are those that are active primarily during twilight (that is, the periods of dawn and dusk). This is distinguished from diurnal...
No
NocturnalNocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal",...
Ca
CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
In
InsectivoresAn insectivore is a carnivorous plant or animal that eats insects. An alternative term is entomophage, which also refers to the human practice of e...
Te
TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
Te
TerritorialA territory is a sociographical area that which an animal consistently defends against the conspecific competition (or, occasionally, against anima...
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Torpor is a state of decreased physiological activity in an animal, usually marked by a reduced body temperature and metabolic rate. Torpor enables...
Mo
MonogamyMonogamy is a form of relationship in which both the male and the female has only one partner. This pair may cohabitate in an area or territory for...
So
SolitaryPa
Partial MigrantPartial migration is when within a migratory species or even within a single population, some individuals migrate while others do not.
C
starts withThis is the smallest North American nightjar, about 18 centimetres (7.1 in) in length, with a wingspan of approximately 30 centimetres (12 in). It weighs 36–58 grams (1.3–2.0 oz). The sexes are similar, both gray and black patterned above. The outer tail-feathers are tipped with white, the markings slightly more prominent in the male.
The common poorwill is told from similar nightjars by its small size, short bill, rounded wings with tips that reach the end of the short tail at rest, and pale gray coloration. Like many other nightjars, the common name derives from its call, a monotonous poor-will given from dusk to dawn. At close range a third syllable of the call may be heard, resulting in a poor-will-low. It also gives a chuck note in flight.
The common poorwill is the only bird known to go into torpor for extended periods (weeks to months). This happens on the southern edge of its range in the United States, where it spends much of the winter inactive, concealed in piles of rocks. This behavior has been reported in California and New Mexico. Such an extended period of torpor is close to a state of hibernation, not known among other birds. It was described definitively by Dr. Edmund Jaeger in 1948 based on a poorwill he discovered hibernating in the Chuckwalla Mountains of California in 1946.
In 1804, Meriwether Lewis observed hibernating common poorwills in North Dakota during the Lewis and Clark Expedition. Though these observations were recorded carefully in Lewis's journal, their significance was not understood. This was at least in part because the common poorwill was not then recognized as a species distinct from the whip-poor-will of eastern North America. Native Americans of the Hopi tribe were likely aware of the poorwill's behavior even earlier — the Hopílavayi name of this bird, hölchko, means "The Sleeping One".
Like other members of this family it feeds on nocturnal insects such as moths, beetles, and grasshoppers. It ejects pellets of the indigestible parts, in the manner of an owl. The common poorwill frequently takes prey off of the ground or by leaping into the air from the ground. It is reported to drink on the wing.
Breeding is from March to August in the south of the range, and late May to September further north. The nest of the common poorwill is a shallow scrape on the ground, often at the base of a hill and frequently shaded partly by a bush or clump of grass. The clutch size is typically two, and the eggs are white to creamy, or pale pink, sometimes with darker mottling. Both sexes incubate for 20–21 days to hatching, with another 20–23 days to fledging. There is usually one brood per year, but females may sometimes lay and incubate a second clutch within 100 m of the first nest while the male feeds young at the first site. The young are semiprecocial. An adult disturbed on the nest tumbles and opens its mouth, hissing, apparently imitating a snake.
