Data Base BL 2

This experimental study explores the partial contribution of uropygial gland secretion to final colouration of nestling mouth-flanges. The main findings of our study are that after cleaning, flanges were brighter, more UV and less yellow-red coloured (chroma). Our findings therefore support the hypothesis that nestlings use their uropygial secretion as cosmetics, and open the possibility for future research to investigate the role of uropygial secretion in reinforcing the signalling role of begging-related traits involved in parent-offspring communication.