By Susan Milius
Among the little European birds called blue tits, it’s the yellow feathers that mark a good dad.
That’s the conclusion of a novel experiment by Juan Carlos Senar and his colleagues at the Museu de Zoologia in Barcelona. They’ve been investigating what information flashy male-bird feathers might reveal to females. Studies in several other birds, such as house finches, have shown that females prefer males with plenty of the orange-yellow carotene pigments in their feathers. Senar wondered whether yellow advertises good genes or behavioral traits that make for good parenting.