Science Study Explains The Sexy Glow Of Parrot Plumage

New findings on parrot plumage are reported in the 4 January 2002 issue of the international journal, Science, published by the American Association for the Advancement of Science.

An ingenious experiment with budgerigar birds--completed by Kathryn E. Arnold of the University of Glasgow in Scotland and colleagues-- suggests that the birds derive some of their sex appeal from the fluorescence of their feathers. Fluorescent pigments appear to "glow" when they absorb and re-emit ultra-violet (UV) light at longer wavelengths.

The researchers tested for evidence of fluorescent sexual signaling in the birds by applying sunscreen to the bright yellow crown feathers of males and females, to reduce the UV absorption of the plumage, consequently "dulling" their fluorescence.

The result: Both male and female budgies showed a significant sexual preference for brightly glowing (fluorescent) companions, compared to their sunscreen-slicked rivals. This suggests that natural fluorescence may be an adaptive signal in the birds, rather than a simple byproduct of their feather coloring.

With Kathryn Arnold, co-authors on this Science study were Ian P.F. Owens at the Imperial College at Silwood Park, U.K.; and N. Justin Marshall, University of Queensland, Australia.