The intensity threshold of colour vision in a passerine bird, the blue tit (Cyanistes caeruleus)

D. Gomez, A. Gregoire, M. Del Rey Granado, M. Bassoul, D. Degueldre, P. Perret, C. Doutrelant
2014 Journal of Experimental Biology  
Many vertebrates use colour vision for vital behaviour but their visual performance in dim light is largely unknown. The light intensity threshold of colour vision is known only for humans, horses and two parrot species. Here, we first explore this threshold in a passerine bird, the blue tit (Cyanistes caeruleus). Using classic conditioning of colour cues to food rewards in three individuals, we find a threshold ranging from 0.05 to 0.2 cd m −2 . Results are comparable to the two previously
more » ... two previously tested bird species. For tits, nest light conditions probably exceed that threshold, at least after sunrise. These results shed new light on the lively debate questioning the visual performance of cavity nesters and the evolutionary significance of egg and chick coloration. Although this needs further investigation, it is possible that blue tits exploit both colour and brightness cues when viewing their eggs, chicks or conspecifics in their nests.
doi:10.1242/jeb.107573 pmid:25214487 fatcat:nlakw7zuhnfmzmntzdnxmeupnu