[1] The nighthawk's subfamily consists of four genera: Chordeiles; Swainson, 1832, Lurocalis; Cassin, 1851, Podager; Wagler, 1832, and Nyctiprogne; Bonaparte, 1857, which are all native to the western hemisphere.

[6][7] Fossil records indicate that specimens later identified to be the common nighthawks (Chordeiles minor) excavated in the Southwestern US could be traced back as far as 400,000 years (during the Pleistocene era) meaning that the subfamily has been an entrenched component of new world ecology for a significant duration of time.

[12] To promote concealment during the day, some species perch facing lengthwise along a branch, rather than across it as birds usually do.Nighthawks are generally solitary but form flocks for the purpose of migration and for elaborate mating displays.

[14] Males will defend the nesting area, demonstrating indiscriminate aggression with displays involving diving and the production of a booming noise using their wings which deters predators and others of the same species.

[15] This unselective hostility can result in a decline in the average proportion of breeding individuals in a population in densely occupied territories, even below that of the carrying capacity established by available resources.

[15] Nighthawks are mostly active in the late evening and early morning or at night and feed on moths and other large flying insects by holding their beak open in flight.

[18] During the day, nighthawks roost in forested areas which provide them with cover from both predators and temperature fluctuations, although they may also occasionally be observed in grasslands and early successional habitats rich in foraging opportunities.

[20] Further research has determined that, in addition to this annual migration between general regions, nighthawks demonstrate a high breeding site fidelity, thus meaning they are especially susceptible to destabilization as a result of natural disasters such as forest fires, floods or droughts, as well as anthropogenic interventions such as development.