Data from: Mutual plumage ornamentation and biparental care: consequences for success in different environments

According to the good parent and differential allocation models, parental behavior could depend on the individual’s own quality, and it could be adjusted to the coinvestor’s parental care and sexual ornamentation. These investment patterns may interact with environmental conditions and offspring quality in determining reproductive success. Few studies have considered ornament-related own and partner care of both parents and their consequences in relation to environmental conditions. In a brood size manipulation experiment on collared flycatchers (Ficedula albicollis), we measured nestling feeding rates, white patch sizes and plumage reflectance properties of both parents, and quantified nestling growth and reproductive success. We found little relationship between ornamentation and own feeding rate irrespective of manipulation. Parental quality, measured as nestling biomass production per unit feeding effort, was related to male structural plumage brightness in a manipulation-dependent manner. Male wing patch size and the female’s structural plumage brightness were linked to the partner’s feeding rate, and this did not vary with experimental environment. Finally, relationship of pre-fledging nestling size with male forehead patch size was environment-dependent, and this pattern was apparently due to intrinsic nestling characteristics. Reproductive success only partly reflected these findings. Our results indicate how integrated studies of mutual ornamentation and mutual care with environmental and offspring quality may help us better grasp the selection forces shaping sexual ornaments.