Eric Medard / Nightjar (Caprimulgus europaeus) in flight at sunset, France. June.

Eric Medard / Nightjar (Caprimulgus europaeus) in flight at sunset, France. June.

Eric Medard / Nightjar (Caprimulgus europaeus) resting during the day, France. June.

Eric Medard / Nightjar (Caprimulgus europaeus) at night, taken with infra red camera. France. June.

Andres M. Dominguez / Red-necked nightjar (Caprimulgus ruficollis) on nest with eggs, Arcos de la Frontera, southern Spain, May

Matthew Maran / Isolated Scots pines (Pinus sylvestris) on the East Devon Pebblebed Heaths which provides popular churring / calling locations for the nightjar (Caprimulgus europaeus) Devon, England, UK, May 2014.

Chien Lee / Madagascar Nightjar (Caprimulgus madagascariensis) camouflaged on ground, Madagascar

Barry Mansell / Whip-poor-will (Caprimulgus vociferus) female on nest, North Florida,USA

Alan Murphy/ BIA / Pauraque (Nyctidromus albicollis) camouflaged in leaf litter, Texas

Graeme Guy/ BIA / Large-tailed Nightjar (Caprimulgus macrurus) mother with chicks, Singapore

Jan Wegener/ BIA / Common Nighthawk (Chordeiles minor) flying, Texas

Jan Wegener/ BIA / Common Nighthawk (Chordeiles minor), Texas