Common nighthawk

Nighthawks hunt at dawn and dusk, catching insects in flight with their wide mouths. Males court by diving towards the ground and pulling up sharply, the air through their wings making a loud "boom".

They nest on bare ground or on flat gravel rooftops, laying eggs directly on the surface.

Common nighthawks eat vast numbers of flying insects, and one migrating flock can include hundreds of birds. They have declined sharply across North America, partly because gravel roofs are being replaced by smooth membranes that do not suit nesting, and partly because insect numbers have fallen.

Nest — No nest; eggs laid on bare gravel, sand or rock, or a flat gravel roof
Eggs — Usually two
Incubation — About 16 to 20 days
Chicks — Covered in down, able to move short distances soon after hatching
Flight — At about three weeks
Lifespan — Wild birds over nine years are recorded

• A nighthawk on a flat roof or gravel car park in summer may be sitting on eggs; leaving it be for a few weeks is enough.
• A nighthawk sitting still on the ground is not necessarily injured; they rest on the ground and on branches, lying along them rather than across.
• Grounded nighthawks cannot easily take off from flat surfaces if hurt or cold; a rehabilitator can help.

• Nighthawks are hawks. They are nightjars, related to whip-poor-wills, and eat only insects.
• A bird lying flat on gravel is dead or dying. Nighthawks rest flat and rely on camouflage.

• Chuck-will's-widow
• Eastern whip-poor-will
• Chimney swift