The effects of the light environment on prey choice by zebra finches

Recent research has highlighted the extent to which birds utilise ultraviol et vision in mate choice and foraging. However, neither the importance of t he ultraviolet compared with other regions of the visual spectrum nor the u se of wavelength cues in other visual tasks have been explored. We assessed the individual choices of zebra finches (Taeniopygia guttata) for differen t-coloured seeds (red and white millet) under lighting conditions in which filters selectively removed blocks of the avian-visible spectrum correspond ing to the spectral sensitivity of the four retinal cone types that subserv e colour vision in this species. The effects corresponded to those predicte d from the calculated distances between seed types, and between each seed t ype and the background, in a simple model of tetrachromatic colour space. A s predicted for this foraging task, the removal of long-wavelength informat ion had a greater influence than the removal of shorter wavelengths, includ ing ultraviolet wavelengths. These results have important implications for predator-prey interactions and suggest that future studies of natural forag ing should consider variations in the light environment.