Oxidative status in nestlings shows different associations with parental carotenoid-based plumage ornaments depending on parental sex and year: a study of rock sparrows Petronia petronia

Carotenoid-based colouration in birds has been suggested to be a sexually selected signal, allowing individuals to obtain reliable information about the quality of antioxidant resources. Moreover, oxidative stress levels during early development may have medium- and long-term fitness consequences. Rock sparrows (Petronia petronia) display a carotenoid-based breast patch in both sexes which has been shown to function as a signal of phenotypic quality in sexual and social interactions. We studied a rock sparrow population in central Spain aiming to test whether the extent of the carotenoid-based breast patch is associated with offspring growth and oxidative status. We have used plasma malondialdehyde (MDA) level in plasma as a measure of oxidative damage, and total antioxidant status of plasma (TAS) and total glutathione (tGSH) levels in red blood cells as measures of antioxidant defences. The study included the extremely late breeding season of 2013 and the phenologically more normal season of 2014. Unfavo...