Ultraviolet colour vision and ornamentationin bluethroats

Many birds see in the ultraviolet (300^400 nm), but there is limited evidence for colour communication (signalling by spectral shape independently of brightness) in this hidden’ waveband. Such data are critical for the understanding of extravagant plumage colours

STAFFAN ANDERSSON AND TROND AMUNDSEN, Proc. R. Soc. Lond. B (1997) 264, 1587-1591