Nightjars are mysterious crepuscular birds of heathland and young plantations whose distinctive churring calls announce summer evenings. Their welfare depends on open, sparsely vegetated habitats with large moth prey populations.
Nightjar welfare during breeding is primarily affected by disturbance from dogs and people at night on heathland. Their extreme camouflage makes nests essentially invisible to walkers, and dogs locate them by scent. Nightjars flushed from nests at night cannot defend eggs or chicks against predation and the thermal shock of exposed eggs in cool night air. Crepuscular watching behaviour -- large groups gathering on heathland at dusk to hear and see nightjars -- can prevent birds from leaving cover if observers position too close to cover used by the birds.