The Common Nighthawk is a fascinating bird with some unique behaviors and adaptations. Here are some interesting facts about this nocturnal bird:
Physical Description
The Common Nighthawk is a medium-sized bird, measuring around 9 inches in length with a wingspan of over 2 feet. They have long, pointed wings and a short, forked tail. Their plumage is mottled brown, gray, and white, providing great camouflage as they roost during the day. A distinctive white bar is visible across their wings when in flight.
One of the most noticeable features of the Common Nighthawk is its small, rounded head and very short, hooked beak. The beak opens wide to scoop up flying insects. They have large eyes adapted for seeing in low light conditions.
Common Nighthawks do not have a true song but make a loud “peent” call when interacting or establishing territories. The name “nighthawk” comes from this loud, nasal vocalization.
Range and Habitat
Common Nighthawks are found throughout much of North America. Their breeding range extends from southern Canada through the United States and into Mexico. They migrate south to winter in South America.
During the breeding season, Common Nighthawks can be found in a variety of open habitats including forest clearings, grasslands, sagebrush deserts, savannahs, open woodlands, rock outcroppings, gravel beaches and recently burned areas. They avoid dense forest and heavily urbanized areas.
On migration and in their wintering range, Common Nighthawks use similar open and semi-open habitats.
Migration
The Common Nighthawk is one of North America’s long-distance migrants. They winter in South America, traveling over 5,000 miles between their breeding and wintering grounds each year.
Their spring migration north takes place over a broad front across North America, with birds arriving on breeding grounds from mid-April to early June. In the fall, they gather in large flocks migrating south beginning in late July through October.
Common Nighthawks are sometimes seen migrating during the day but mostly travel at night. They navigate by the stars and may gather in concentrations along migration routes.
Breeding
Common Nighthawks do not build nests. Instead, they lay their eggs directly on bare ground such as gravel rooftops, exposed rocky outcrops, burnt-over areas, loose sand, or exposed soil.
The female lays a clutch of two pea-sized eggs, often with little separation between them. Incubation lasts for 18 to 20 days. The eggs are so well camouflaged that they are nearly impossible to see.
Once hatched, the chicks are semi-precocial. They are covered in down and able to move around but rely on their parents for food and keeping warm for the first couple of weeks. The young fledge at around 18 to 20 days old.
Diet
Common Nighthawks are insectivores, feeding almost exclusively on flying insects. Some of their common prey includes beetles, flies, winged ants, moths, mayflies, grasshoppers, and crickets.
They hunt on the wing, using their large mouths and gaping bills to scoop up insects in flight. Their feeding patterns often parallel peak insect activity at dawn and dusk but they also forage at night by moonlight or in the glow of urban light pollution.
Aerial Displays
One of the most fascinating behaviors of the Common Nighthawk is the aerial displays performed by the males during courtship. These displays begin in late spring as the birds return to their breeding grounds.
To attract females, the males fly high in the sky then swoop down rapidly with a loud booming noise. This booming, diving display is created through a combination of wing beats and by spreading their long, tapered wings to create wind resistance and vibration.
The displays may also involve spirals, loops and dives as the male plummets towards earth before pulling up sharply. This courtship behavior ceases once the female has been attracted for mating.
Roosting
During the daytime, Common Nighthawks roost on bare ground or gravel that matches their camouflage. If needed, they may also roost on branches, fence posts, or even on top of buildings.
In the evening, they leave their roosts to feed. Their activity patterns peak at dawn and dusk but they are also active on warm, moonlit nights.
If temperatures drop or it rains, Common Nighthawks are unable to hunt as flying insects become inactive. During these times, they may enter torpor to conserve energy.
Predators and Threats
The most common predators of nighthawks are hawks and falcons who hunt them on the wing during the daytime. Snakes and ground predators like foxes may raid unattended nests.
One of the main threats to Common Nighthawk populations is the decline of flying insects due to pesticide use. They are also vulnerable to habitat loss as human development encroaches onto breeding areas and native grasslands are lost.
Their attraction to roosting on gravel rooftops makes them susceptible to nest failure and mortality due to disturbances. The species has declined significantly in the last few decades.
Interesting Facts
- Common Nighthawks are the only nighthawks found in North America. Despite their name, they are not closely related to hawks.
- They are sometimes observed hunting on the wing over forest fires, benefiting from the swarm of insects trying to escape the flames.
- Common Nighthawks lack a true songbird syrinx and are not capable of melodious calls. They primarily vocalize with nasal peents.
- Their Latin name Chordeiles minor means “minor chord”, likely in reference to their booming courtship dives.
- The bar of white feathers across their wings may serve to startle and flush up insects during their feeding flights.
- Common Nighthawks breed earlier in the south of their range. Those that breed further north migrate greater distances.
- They roost in groups during migration, sometimes numbering in the thousands of birds at a single stopover site.
- Their large mouths allow them to feed on the wing without landing. They catch thousands of insects each night.
- Common Nighthawks are sometimes observed migrating during the day, unlike many other nocturnal migrants.
- Due to their camouflage and habit of roosting on the ground, Common Nighthawk nests and young are very difficult to locate.
Conclusion
The Common Nighthawk is an aerial acrobat, gracefully hunting insects on the wing. Its flashy mating displays, loud calls, nocturnal behaviors, and long-distance migration make it one of North America’s most fascinating birds. Although their populations have declined, it is still possible to observe these intriguing birds on summer evenings as they dart and boom across the night sky.