Chordeiles minor (J.R.Forster, 1771)

Distinguishing Morphological Traits

The common nighthawk, Chordeiles minor, can be distinguished from other caprimulgids by several traits: a forked tail that bears a white bar in males, long, unbarred, pointed wings with distinct white patches, an absence of rictal bristles, and a characteristic, unmistakable call that serves as a key identification feature.

Size Measurements

This species measures 21 to 25 cm (8.3 to 9.8 in) in total length, with a wingspan of 51 to 61 cm (20 to 24 in). Body mass ranges from 55 to 98 g (1.9 to 3.5 oz).

Standard Morphometrics

Standard measurements are as follows: wing chord 17.2 to 21.3 cm (6.8 to 8.4 in), tail 13 to 15.1 cm (5.1 to 5.9 in), bill 0.5 to 0.8 cm (0.20 to 0.31 in), and tarsus 1.2 to 1.6 cm (0.47 to 0.63 in).

Similar Sympatric Nighthawk Species

The common nighthawk is visually similar to both the Antillean nighthawk and the lesser nighthawk, and it occurs at least seasonally across the entire North American range of both species.

Differences from Lesser Nighthawk

The lesser nighthawk is smaller, and has more buff-colored plumage on its undertail coverts, while the common nighthawk has white undertail coverts. Both common and Antillean nighthawks have entirely dark coloring on the basal portion of their primary feathers, whereas lesser nighthawks have bands of buffy spots here. Common and Antillean nighthawks also have a longer outermost primary, which creates a pointier wing tip than that of the lesser nighthawk.

Foraging and Call Differences from Lesser Nighthawk

The common nighthawk forages at higher heights above ground than the lesser nighthawk and has a different call.

Distinction from Antillean Nighthawk

The only reliable, non-disturbing way to distinguish the common nighthawk from the Antillean nighthawk is also by call differences. Visually, the two species can only be reliably told apart when examined in the hand, and subtle differences make field identification challenging.

Habitat Range and Elevation

The common nighthawk inhabits forests, deserts, savannahs, beaches, desert scrub, cities, and prairies, at elevations from sea level (or below) up to 3,000 m (9,800 ft).

Preferred Nesting Habitat

Nighthawks prefer to nest in edge and early successional habitats, so they are one of the few bird species that will live and hunt in burned or clearcut forest patches.

Urban Habitat Association

The common nighthawk is attracted to urban built-up areas by the insects found there. It is the only nighthawk species that occurs across most of northern North America.

Habitat Suitability Drivers

Food availability is likely a key factor that determines which areas are suitable for habitation and when.

Migration and Survival Drivers

The common nighthawk is not well adapted to survive poor conditions, especially low food availability, so a consistent food supply that coincides with warmer temperatures drives its migration and is critical to its survival.

Torpor Use

It was historically thought that the common nighthawk cannot enter torpor, though recent evidence suggests it does.

Breeding Season Timing

The common nighthawk breeds from mid-March to early October. It most often produces only one brood per breeding season, though a second brood is sometimes produced. It is assumed to breed every year.

Breeding Behavior Traits

There are reports of female common nighthawks reusing nests in subsequent years, and monogamy has recently been confirmed for the species. Courting and mate selection partially occur in flight.

Male Courtship Displays

Males perform diving displays and produce booms (detailed in the vocalization section) to attract female attention; the female may be either flying or stationary on the ground during this. Copulation occurs after the pair settles together on the ground.

Pre-Copulation Displays

During this time, the male rocks his body, wags his fully spread tail, holds his throat bulging, and produces guttural croaking sounds. He repeats this display until copulation occurs.

Preferred Breeding Nesting Habitat

Preferred breeding and nesting habitat includes forested regions with large rocky outcrops, clearings, burned areas, and small patches of sandy gravel. Instead of laying eggs in a constructed nest, common nighthawks lay their eggs directly on bare rock, gravel, or sometimes on a living substrate such as lichen.

Breeding Site Preferences

Agricultural breeding sites are least popular. Since the latter part of the 20th century, urban breeding has been in decline.

Urban Nesting Sites

When urban breeding does occur, it is most often seen on flat gravel rooftops.

Nest Spacing Behavior

The common nighthawk is a solitary nester that places large distances between its nest and nests of other common nighthawk pairs, though its nest is more commonly found closer to nests of other bird species.

Incubation Responsibilities

Females choose the nest site and are the primary incubators of the eggs; males will incubate occasionally. Incubation time varies, but is approximately 18 days.

Nest Attendance Patterns

The female leaves the nest unattended during the evening to feed. The male roosts in a nearby tree, and he changes his roost spot daily; he guards the nest by diving, hissing, beating his wings, or booming at intruders.

Predation Response

When faced with predation, common nighthawks do not easily abandon the nest; instead, they typically rely on their cryptic coloration to camouflage themselves. If they do leave the nest, females have been observed flying away while hissing at the intruder or performing a disturbance display.

Foraging Flight Traits

The common nighthawk is a frequent flyer, with long wings, and hunts while flying for long periods at high altitudes or in open areas. It is crepuscular, and its preferred food source is flying insects.

Foraging Timing

Hunting ends as dusk falls into full night, and resumes again at dawn. Nighttime feeding in complete darkness is rare, even on evenings with a full moon.

Prey Selection Behavior

While the common nighthawk feeds opportunistically, it can adjust its prey choice immediately before capture. Studies show common nighthawks prefer to eat beetles (Coleopterids) and bees, ants, and wasps (Hymenopterids), and will actively seek out these insects in their habitats.

Diet Composition

Although moths and butterflies (Lepidopterans) are the most common type of insect found in the common nighthawk's diet, the species actively avoids eating flies (Dipterids).

Prey Detection Sense

Vision is presumed to be the main sense the common nighthawk uses to detect prey; there is no evidence supporting the use of echolocation.

Artificial Light Foraging

Common nighthawks have been observed gathering around artificial light sources to forage for insects that are attracted to the light.

Flight Speed

The average flight speed of common nighthawks is 23.4 km/h (14.5 mph).