Eastern Bonellis Warbler (Phylloscopus orientalis) Science Article 1
Adult birds replace their flight feathers (moult) at least once per year, either in summer aftertermination of breeding or (in the case of some long-distance migratory species) in the winterquarters. We reconstructed the evolutionary pathways leading to summer and winter moultusing recently published molecular phylogenetic information on the relationships of theWestern Palearctic warblers (Aves: Sylviidae). Our phylogenetic analysis indicates thatsummer moult is the ancestral pattern and that winter moult has evolved 7-10 times in thisclade. As taxa increased their migratory distance and colonized northern breeding areas,summer moult disappeared and winter moult evolved. Our data also allows us to trace thehistorical origins of unusual moult patterns such as the split-moult and biannual moultstrategies: the most parsimonous explanations for their origins is that they evolved fromancestral states of summer moult. We briefly discuss our results in the light of recent criticismsagainst phylogenetic comparative methods and the utility of historical versus functionaldefinitions of adapation.
E. Svensson and A. Hedenstrom, Biological Journal of the Linnean Society (1999), 67: 263-276