Measurements
Both Sexes
- Length
- 8.7–9.4 in
22–24 cm - Wingspan
- 20.9–22.4 in
53–57 cm - Weight
- 2.3–3.5 oz
65–98 g
Relative Size
- Slightly smaller than an American Kestrel; larger than a Purple Martin.
Other Names
- Engoulevent d'Amerique (French)
- Tapacamino zumbón (Spanish)
Cool Facts
- On summer evenings, keep an eye and an ear out for the male Common Nighthawk’s dramatic “booming” display flight. Flying at a height slightly above the treetops, he abruptly dives for the ground. As he peels out of his dive (sometimes just a few meters from the ground) he flexes his wings downward, and the air rushing across his wingtips makes a deep booming or whooshing sound, as if a racecar has just passed by. The dives may be directed at females, territorial intruders, and even people.
- The Common Nighthawk’s impressive booming sounds during courtship dives, in combination with its erratic, bat-like flight, have earned it the colloquial name of “bullbat.” The name “nighthawk” itself is a bit of a misnomer, since the bird is neither strictly nocturnal—it’s active at dawn and dusk—nor closely related to hawks.
- Many Late Pleistocene fossils of Common Nighthawks, up to about 400,000 years old, have been unearthed between Virginia and California and from Wyoming to Texas.
- Common Nighthawks, which have one of the longest migration routes of all North American birds, sometimes show up far out of range. They have been recorded in Iceland, Greenland, the Azores, the Faroe Islands, and multiple times on the British Isles.
- The oldest Common Nighthawk on record was 10 years old.
Habitat
Grassland
Common Nighthawks nest in both rural and urban habitats including coastal sand dunes and beaches, logged forest, recently burned forest, woodland clearings, prairies, plains, sagebrush, grasslands, open forests, and rock outcrops. They also nest on flat gravel rooftops, though less often as gravel roofs are being replaced by smooth, rubberized roofs that provide an unsuitable surface. During migration, Common Nighthawks stop in farmlands, river valleys, marshes, coastal dunes, and open woodlands. Their South American wintering habitat is not well known.
Food
Insects
Common Nighthawks eat flying insects almost exclusively. The Common Nighthawk hunts on the wing at dawn and dusk, opening its tiny beak to reveal a cavernous mouth well suited for snapping up flying insects. It often takes advantage of clouds of insects attracted to streetlamps, stadium lights, and other bright lights. Nighthawks eat queen ants, wasps, beetles, caddisflies, moths, bugs, mayflies, flies, crickets, grasshoppers, and other insects. They may also eat a small amount of vegetation. Though they forage in low light, they seem to locate prey by sight, possibly with the help of a structure in their eyes that reflects light back to the retina to improve their night vision. They occasionally forage during the day in stormy weather, but seem to never forage at night. Common Nighthawks may forage near the ground or water, or more than 500 feet into the sky.
Nesting
Nesting Facts
- Clutch Size
- 2 eggs
- Number of Broods
- 1-2 broods
- Egg Length
- 1.2 in
3 cm - Egg Width
- 0.8 in
2.1 cm - Incubation Period
- 16–20 days
- Nestling Period
- 17–18 days
- Egg Description
- Creamy white to pale olive gray, heavily speckled with gray, brown, and black.
- Condition at Hatching
- Active and sparsely covered with down (dark gray above and creamy below), with eyes half or fully open.
Nest Description
Common Nighthawks lay eggs directly on the ground, which may consist of gravel, sand, bare rock, wood chips, leaves, needles, slag, tar paper, cinders, or living vegetation, such as moss, dandelion rosettes, and lichens.
Nest Placement
Ground
The female probably selects the nest site, usually on unsheltered ground, gravel beaches, rocky outcrops, and open forest floors. Nests are typically out in the open, but may also be near logs, boulders, grass clumps, shrubs, or debris. In cities, Common Nighthawks nest on flat gravel roofs.
Behavior
Aerial Forager
Common Nighthawks are most active from half an hour before sunset until an hour after sunset, and again starting an hour before sunrise (ending about 15 minutes after the sun comes up). They fly with looping, batlike bouts of continuous flapping and sporadic glides. Common Nighthawks are usually solitary, but they form large flocks during migration and males sometimes roost together. Large migrating flocks are most conspicuous in early evening, particularly as the birds gather above billboards and other bright lights to feed on insects. During the breeding season they are generally very territorial but in some areas may have overlapping territories. Males court females by diving through the air, making a booming sound as air rushes over their wings. The male eventually lands on the ground before the female, spreading and waggling his tail, and puffing out his throat to display his white throat patch, while croaking at her. Females incubate the eggs and young, leaving them unattended in the evening to feed. Both males and females feed regurgitated insects to their chicks. Parents perform diversion displays to draw intruders away from the nest. Common Nighthawks may be chased from feeding and breeding areas by smaller, more maneuverable bats and Lesser Nighthawks.
Conservation
Least Concern
Common Nighthawks are still numerous but they appear to be declining in both Canada and the U.S. Hard numbers are difficult to come by because the birds’ cryptic colors and nearly nocturnal habits make them difficult to count during standardized surveys such as the North American Breeding Bird Survey. Recent data suggest the species’ numbers may have dropped by as much as half in Canada since the mid-1960s. Across North America, threats include reduction in mosquitoes and other aerial insects due to pesticides, and habitat loss including open woods in rural areas and flat gravel rooftops in urban ones. Nighthawks are also vulnerable to being hit by cars as they forage over roads or roost on roadways at night. People have had some success creating nesting habitat by placing gravel pads in the corners of rubberized roofs and by burning and clearing patches of forest to create open nesting sites.
Credits
- Brigham, R. M., J. Ng, R.G. Poulin and S.D. Grindal. 2011. Common Nighthawk (Chordeiles minor). In The Birds of North America, No. 213 (A. Poole, ed.). The Birds of North America Online, Ithaca, New York.
- Sauer, J.R., J.E. Hines, J.E. Fallon, K.L. Pardieck, D.J. Ziolkowski Jr., and W.A. Link. 2011. The North American Breeding Bird Survey, Results and Analysis 1966–2010. Version 12.07.2011. USGS Patuxent Wildlife Research Center, Laurel, MD.
- USGS Patuxent Wildlife Research Center. 2011. Longevity Records of North American Birds.
Migration
Long-distance migrant. Common Nighthawks migrate at all hours of the day in large flocks, on one of the longest migration routes of any North American bird. Most travel over land through Mexico and Central America, although many do pass through Florida and Cuba, flying over the Gulf to reach their wintering grounds in southern South America. Common Nighthawks are among the last migrants to return to their breeding grounds in spring.
Find This Bird
Common Nighthawks are easiest to see in flight at dawn and dusk as they forage for aerial insects. Pick a high overlook with a good view of a river, if possible. In towns, look for nighthawks over brightly lit areas such as billboards, stadium lights, and streetlights. Scan the darkening sky and you’ll likely find some bats zipping around with their frenzied flapping—but look for a larger, bounding, long-winged shape. If you don’t see one, listen for low, buzzy peent calls. If you are in an area with breeding nighthawks, pay attention for the bizarre booming noise of a territorial or courtship flight.