The goatsuckers, nightjars, and nighthawks are more than 70 species of birds in the family Caprimulgidae. These birds have a relatively large head, with a wide beak, and a large mouth with a seemingly enormous gape. The mouth is fringed by long, stiff bristles, and is an adaptation for catching insects in flight. The unusually large mouth of goatsuckers was once believed to be useful for suckling milk at night from lactating goats. This was, of course, an erroneous folk belief, but it is perpetuated today in the common name of the family of these birds.
Most goatsuckers and nightjars have long, pointed wings, and short, feeble feet. Most species are crepuscular, being active mostly in dim light around dusk. Some species are nocturnal, or active at night. The colors of these birds are subdued, mostly consisting of drab, streaky browns, blacks, and grays. This coloration makes goatsuckers and nightjars very well camouflaged, and they can be exceedingly hard to detect during the day, when they are roosting or sitting on a nest.
This family of birds is richest in species in Africa and south Asia. There are only eight species of goatsuckers in North America, most of which are migratory species, breeding in North America and wintering in Central and South America.
One of the most familiar species of goatsuckers in North America is the whip-poor-will (Caprimulgus vociferus ), occurring throughout the eastern United States and southeastern Canada. Unfortunately, the population of this species has declined over much of its range, due to the large loss of natural habitat, and the fragmentation of the remnants.
Chuck-will’s-widow (C. carolinensis ) occurs in pine forests of the southeastern United States, while the common poorwill (Phalaenoptilus nuttallii ) is the most common goatsucker in the western United States. The common names of the whip-poor-will, poorwill, chuck-will’s-widow, and the pauraque (Nyctidromus albicollis ) of southern Texas have all been derived from the very distinctive, loud calls made by these birds. Naming animals after the sounds that they make is known as onomatopoeia.
The common nighthawk (Chordeiles minor ) is another relatively familiar species, ranging through all of the United States and much of Canada. This species is highly aerial when hunting, swooping gracefully and swiftly on its falcon-like wings to capture its prey of moths, beetles, ants, and other flying insects. The common nighthawk tends to breed in open, rocky places, and it also accepts flat, gravelly roofs in cities as a nesting base. Most urban residents are not aware that breeding populations of this native bird occur in their midst, although they may have often wondered about the source of the loud “peeent” sounds that nighthawks make while flying about at dusk and dawn. For reasons that are not understood, populations of the common nighthawk appear to be declining markedly, and the species may be in jeopardy. The lesser nighthawk (C. acutipennis ) is a smaller species that occurs in the southwestern United States.
The poorwill (Phalaenoptilus nuttallii ) of the western United States is the only species of bird that is known to hibernate. This has not been observed many times, but poorwills have occasionally been found roosting in crevices in canyons in winter, in an obviously torpid state, and not moving for several months. These hibernating birds maintain a body temperature of only 95.4-97.2°F (18-19°C), compared with their normal 135-136.8°F (40-41°C).
The Puerto Rican nightjar (Caprimulgus noctitherus ) is a rare species that only occurs on the Caribbean island of Puerto Rico. Only about 1,400-2,000 individuals of this critically endangered species survive. The Puerto Rican nightjar has been decimated by losses of its natural habitat, especially deforestation, and by depredations by introduced predators, such as the mongoose.
del Hoyo, J., A. Elliott, and J. Sargatal. Handbook of the Birds of the World. Vol. 5, Barn-owls to Hummingbirds. Barcelona: Lynx Edicions, 1999.
Forshaw, Joseph. Encyclopedia of Birds. 2nd ed. New York: Academic Press, 1998.
Holyoak, David T. Nightjars and Their Allies. Oxford: Oxford University Press, 2001.