About the Common Nighthawk
This goatsucker performs flight displays and roosts conspicuously. Normally solitary, it sometimes forages or migrates in loose flocks. Polytypic. Length 8.8–9.6".
Varies geographically. Upperparts black to paler brownish gray; crown and upper back darkest; paler markings concentrated on upperwing coverts, scapulars, tertials. Underparts barred blackish brown and white or buff, chest and malar area darker, spotted with buff or dull white. Adult male: white throat patch, subterminal tail band, and primary patch about halfway between bend of wing and wing tip. Adult female: throat patch buffy, primary patch smaller, tail band reduced or lacking. Juvenile: generally paler, more uniform above with finer spotting and vermiculations.
Nine subspecies, 7 in North America. Eastern birds darkest, blackish above, less mottling on back; nominate minor (large), chapmani (smaller). Great Plains-Great Basin-Southwestern birds paler, grayer; henryi (medium size), howelli (large), sennetti (large), and aserriensis (small). Western hesperis relatively dark, grayer, large. Juvenile minor and chapmani blackish; sennetti palest; hesperis, howelli, aserriensis intermediate; henryi rusty.
Position of wing patch, lack of buff spotting on primaries, pointier wing, and darker underwing coverts eliminate lesser. Separation from Antillean problematic; best told by voice, but Antillean also usually smaller, shorter winged, and buffier on belly and undertail coverts.
Call: nasal peent by male in flight; multiple-syllable variation may suggest Antillean. Male courtship dive vibrates primaries, producing “boom.”
Status and Distribution
Common. Breeding: open habitats. Migration: in spring, arrives early April–mid-June, peak May, arrival later in North, West; departs late July–October, peak September, stragglers into November. Winter: South America; casual Gulf Coast. Vagrant: casual/accidental, mainly fall, Hawaii, northern Canada, and United Kingdom.
Some declines in parts of East.
—From the National Geographic book Complete Birds of North America, 2006