Wild common crossbills produce redder body feathers when their wings are clipped
B. Fernandez-Eslava, A. Cantarero, D. Alonso, C. Alonso-Alvarez
The paper shows that clipped-wing male common crossbills develop redder rump feathers than controls, suggesting flight metabolism affects carotenoid conversion to red pigments.
bioRxiv · Mar 28, 2022Evolutionary Biology