Nighthawk
Aiton's Encyclopedia (1910)
a bird closely related to the whip-poor-will and often confounded with it. The nighthawk, bull-bat, or nightjar, as it is called, is a trifle larger than the whip-poor-will. It has darker plumage, with a broader white band on the breast and a conspicuous white bar on the shortest wing coverts. The nighthawk sits lengthwise on the limb of a tree. In prairie regions it rests on the bare ground during the day. Toward nightfall and on cloudy afternoons, or shortly after sunset and until far into the night, it flies at great heights coursing after insects. Diving in mid-air is a favorite exercise. It circles about giving a nasal call as if to attract attention, then dives downward as though to destruction, but turns upward abruptly with a b-o-o-r-r-r-r-r, suggesting the British name of nightjar. "We heard the nighthawk's sullen plunge," says Whittier. The nighthawk breeds in eastern North America from the Gulf to Labrador, and winters in South America . Two dull white eggs with fine grayish brown specks are laid on bare ground in open fields, on the plains, or even on the gravel roofs of city buildings. Nests have been found for many years on the gravel roofs of the Minneapolis flour mills. At eventide the birds swoop around the Falls of St. Anthony in pursuit of insects. Thoreau likens the young to "a pinch of rabbit's fur, or down of that color, dropped on the ground, not two inches long, with a dimpling, somewhat regular arrangement of minute feathers in the middle destined to become the wings and tail."
What Has Changed in the Last Century
The natural history in Aiton's 1910 account still holds: the common nighthawk (Chordeiles minor) does lay two speckled eggs on bare ground, and the diving "b-o-o-r-r-r-r-r" is now known to be mechanical, made by air rushing through the stiff wing feathers as the bird pulls out of its plunge, not a call. Two things have changed sharply. The rooftop nests Aiton praised on the Minneapolis flour mills have largely vanished across North America as flat gravel roofs were replaced with smooth rubber membrane, and the species has declined steeply since the mid-twentieth century, enough for Canada to list it as Threatened in 2007. Naming has tidied up too: "nightjar" is now reserved for the Old World birds and the family as a whole, and the whip-poor-will has been moved to a separate genus, Antrostomus, from the nighthawks.
Written for this edition, 2026.