Feb. 17 - Jackdaws, from the corvid family of birds, use their brightly coloured eyes to warn competitors away from their highly prized nesting boxes during the Spring breeding season, according to a British study. Researchers from the universities of Cambridge and Exeter say it's the first time that a non-primate has been shown to use its eyes to communicate. Jim Drury has more.
The jackdaw nests in tree cavities - using its distinctive eyes to ward off competitors. Gabrielle Davidson, from the University of Cambridge has been studying the birds. She says her research has found the first evidence of a non-primate using its eyes to communicate. She installed one of four different picture cards in 100 jackdaw nests near Cambridge. The pictures showed either a full jackdaw face, a pair of jackdaw eyes on their own, rook's eyes on a jackdaw, or plain black card. She then filmed birds approaching the nest boxes. UPSOT: BIRDS TWEETING SOUNDBITE (English) GABRIELLE DAVIDSON, ANIMAL BEHAVIOUR RESEARCHER AT THE UNIVERSITY OF CAMBRIDGE, SAYING: "What we found was that jackdaws were less likely to approach if the image of the jackdaw with bright eyes was inside the nest box, whereas it made no difference if there was a jackdaw with dark eyes in the nest box....So the jackdaw eyes may actually function as a warning signal competitors to stay away. 'This nest box is occupied, do not approach.'" Jackdaw eyes are white, with striking pale irises, while crows' and other corvids eyes are black. UPSOT: BIRDS TWEETING Davidson says bright eyes may have an evolutionary purpose - to avert the sometimes brutal fights between jackdaws over nesting space. She hopes her research will inspire further study of bird communication. SOUNDBITE (English) GABRIELLE DAVIDSON, ANIMAL BEHAVIOUR RESEARCHER AT THE UNIVERSITY OF CAMBRIDGE, SAYING: "We really know nothing about why some bird species have coloured eyes and this will open the doors to research regarding this and whether birds communicate in other ways, aside from warning signals. Perhaps they co-operate through communication with the eyes." While most birds have black or dark brown eyes, around 10 percent of perching birds, have coloured irises. Whether they too use their eyes to stare down competitors, remains to be seen.