The patch of skin above a hawk's beak just looks orange-yellow to us, but to another hawk, it may broadcast ultraviolet (UV) sex appeal.
For the first time, researchers have shown that this bit of skin, called a cere, strongly reflects light in the UV range. The UV reflection isn't as bright as the orangey light coming from the patch, but it's distinct, report François Mougeot and Beatriz Arroyo of the Center for Ecology and Hydrology in Banchory, Scotland.
Many researchers have focused on orangey carotenoid pigments in both the plumage and the fleshy decorations of birds as possible signals of mate quality and sexiness. But studies have also shown that some of these features, such as grouse combs, flash UV.
Mougeot and Arro