Nightjar  (Caprimulgus europaeus)

Crepuscular: active at dusk.
Cryptic colouration (crypsis).: colouration that makes animals difficult to detect against their background. The colouration may provide camouflage against a background or break up the outline of the body. Both can occur in a single animal, and tend to reduce predation.

1. UNEP-WCMC (November 2001)
   http://quin.unep-wcmc.org
   
2. RSPB (November 2001)
   http://www.rspb.org.uk
   
3. Battern, L. A., Bibby, C. J., Clement, P., Elliott, G. D. and Porter, R.F. (1990) Red Data Birds in Britain. T & A.D. Poyser, London.
   
4. Greenoak, F. (1997) British birds, their folklore, names and literature. Christopher Helm A&C Black, London.
   
5. UK Biodiversity (November 2001)
   http://www.ukbap.org.uk