Extra-pair paternity in the Saffron Finch is related to song peak frequency and body condition

In many avian species, age, body size, and song could signal quality or individual breeding experience and these traits are often correlated with reproductive success. The relationship between sexually selected signals and avian mating systems is a topic of active research, but still remains poorly investigated in species from southern latitudes. Here, we explored the relationships between body size, condition, age, song and social and genetic reproductive success in Sicalis flaveola pelzelni, a Neotropical thraupid. This socially monogamous species has both age-related changes in song and plumage colouration and extra-pair paternity. When measuring male song we found that a lower peak frequency may be associated with patterns of extra-pair paternity gain by males. We also found that male age may not have a marked effect on paternity assurance. In addition, we found that female body condition appears to influence on the proportion of extra-pair nestlings in females' nests. We contribute novel data to help bridge the geographic and taxonomic gap in this research field.