Nightjars are nocturnal heathland birds that nest directly on the ground and are highly vulnerable to disturbance from dog walkers, mountain bikers, and other recreational users of heathland at dusk when the birds are most active.
Nightjars disturbed at the nest by dogs or people flush suddenly, leaving eggs exposed to cooling within minutes. If disturbance is repeated, adults may abandon the nest entirely. Chicks that are separated from adults during disturbance events die from cold and predation. The coincidence of nightjar active periods and evening recreation creates unavoidable welfare risk on popular heathlands without effective visitor management.