Nighthawks and Nightjars (Caprimulgidae)
In the taxonomic order CAPRIMULGIFORMES (pronounced ka-pri-muhl-gih-FOR-meez), there are four families of birds; the frogmouths of Asia and Australia, the similar potoos of Central and South America, the Oilbird, and the nightjars.
Ninety-two species of nightjars and nighthawks in sixteen genera are included in the Caprimulgidae (pronounced ka-pri-MUHL-gih-dee) family, a group found on all continents except for Antarctica.
In North America, twenty-three species of nightjars in seven genera have occurred (including the extinct Jamaican Pauraque). Members of this family include the aerial nighthawks and the vociferous Whip-poor-will.
The nightjars are known for their highly camouflaged (cryptic) plumage and for their distinctive vocalizations, the names of the Whip-poor-will and Chuck-will’s-widow actually sounding like their respective vocalizations.
Small to medium sized birds, members of the Caprimulgidae have large, rounded heads, long wings, longish tails, short legs, and small feet. Their bills are distinctive in being very short but with a wide gape that imparts a large-mouthed appearance upon opening the bill. Rictal bristles bordering the gape aid in catching insect prey.
Shades of brown mixed with gray, white, and black are the predominant colors in the plumages of nightjars. These form beautiful cryptic patterns that resemble dead leaves, rocky ground, and other natural backgrounds. White markings used for signaling are often found on the throat, in the wings, and on the tail.
Nightjars and nighthawks occur in habitats throughout North America except the tundra. The most widespread species is the Common Nighthawk, a bird of open country and clearings that has become adapted to nesting on the flat roofs of buildings. Other species are adapted to eastern and southern woodlands (the Whip-poor-will and Chuck-will’s-widow), non-forest habitats of the west (the Common Poorwill), and deserts (the Lesser Nighthawk). Two species are uncommon or rare – one in southern Florida (the Antillean Nighthawk), and another in southern Arizona (the Buff-collared Nightjar).
All North American members are long distance migrants except for the Common Poorwill, a short distance migrant to Mexico.
Although Common Nighthawks can occur in large flocks during migration, nightjars are typically solitary in nature, and are primarily nocturnal. Nighthawks can also be seen foraging at dusk and dawn as they flutter around for insects in the sky. The other nightjars forage by sallying for insects from perches on the ground or low vegetation.
Nightjars are not endangered in North America although populations of the Whip-poor-will have declined in the northeastern United States as a result of habitat destruction.
To the delight of birders and dismay of some campers, the Whip-poor-will can sing for hours on end during the night. One bird was recorded singing its name over 1,000 times in a row.
The only bird known to hibernate, the Common Poorwill survives the desert winter in southern California by lowering its body temperature to that of its surroundings. The family name of Caprimulgidae literally means “goat sucker” and comes from the old (and incorrect) belief that these birds snuck into barns at night to feed from the udders of milk goats.