Caprimulgidae - Nightjars
Nightjars are one of the most enigmatic of bird groups. Entirely nocturnal, they are aerial insectivores either hunting their prey through the sky, or sallying forth from a perch. It is thought they locate their prey by sight, rather than by echolocation. They are commonest in the tropics, with only a few migratory species venturing into temperate climes. All have a beautfully cryptic plumage with large flashes of white on the underwings or tail, large eyes, and an extraordinarily wide gape.
Only one species, the Nightjar occurs with any regularity in Britain, its distinctive churring call being heard on southern heaths during the summer months.