Wing-feather moult phenotypes differ between the preformative and prealternate episodes and along passerine phylogeny

Passerine wing-feather moult has been studied historically in terms of its intensity, duration, timing and extent. However, little is known about variation of wing-moult phenotypes (i.e. the identity of moulted wing feathers in a given individual) within species, among moult episodes and in relation to passerine phylogeny. Here we studied 5373 wing-moult cards from 285 Holarctic and 155 Neotropical passerine species. Variation of moult phenotypes, although high, was far below that expected by chance, and the same phenotypes were repeated among individuals within and among species, suggesting the existence of shared mechanisms of moult control. We successfully classified moult phenotypes according to nine moult patterns described in the literature and found an uneven distribution between the preformative and the prealternate moult. Moult patterns were phylogenetically conserved for the preformative but not for the prealternate moult. Our results suggest differential seasonal control of bird moult with preformative moults being associated with (evolutionarily conserved) somatic demands, whereas prealternate moults are probably associated with (rapidly evolving) signalling functions.