The male satin bowerbird (Ptilonorhynchus violaceus) has brightly coloured eyes
H Lansdown/Alamy
While birds often have vibrant plumage, the dazzling diversity in the colour of their eyes might be just as important for their survival and reproductive success, according to a review of hundreds of studies on the topic.
Many birds have brightly coloured eyes. The black-and-red-broadbill (Cymbirhynchus macrorhynchos), for instance, has sapphire blue or vivid emerald eyes. The Satin bowerbird (Ptilonorhynchus violaceus) has irises of periwinkle and purple. Some species of green pigeon (in the genus Treron) have magenta peepers …