Interacting effects of signalling behavior, ambient light and plumage colour in a temperate bird, the Blue tit Parus caeruleus

Individuals can increase their conspicuousness to conspecifics while minimizing their probability of detection by predators by choosing the time and location of their display. Conspicuousness arises from the contrast between the light reflected by the colour patches, and the light refl ected by the visual background in ambient light used for displays. Conspicuousness also depends on the discrimination abilities of both conspecifics and predators. We investigated whether different light environments are present in temperate woodlands, and whether male Blue Tits use this variability to optimize intraspecific conspicuousness while reducing the probability of detection by predators. We measured…