One cardinal function of the avian uropygial gland and its oily secretions is protection against micro-organisms that may harm the feathers or developing embryos of the hosts. We studied this hypothesis by the phylogenetic comparative approach across 132 European bird species. Our results lend support for the defence hypothesis because gland size (1) correlated positively with total eggshell surface area, (2) increased much from non-breeding to breeding season in social species and (3) was larger in species inhabiting humid habitats. Our manuscript was recommended for publication in the Biological Journal of the Linnean Society. Authors with asterisk are Evol Ecol group members, while those marked with boldface are supported by a CNCSIS grant (PN II. RU TE 291/2010).

Vincze O*, Vágási CI*, Kovács I, Galván I, Pap PL*. Risk of bacterial infection and the seasonally dynamic activity of the uropygial gland in European birds.