Social environment affects correlates of dominance status in the greenfinch Carduelis chloris

Abstract

Dominance status is responsible for individual variation in access to resources. The relationship between social rank and sex, age, body size, site experience, prior ownership, motivation and fat reserves has been shown to vary among species due to their different natural history. This study investigated these relationships in captive groups of greenfinches Carduelis chloris. Dominance status was measured as the outcome of agonistic interactions in both dyadic and group trials. Results varied according to encounter conditions due to differences in social environment. Beyond sex, asymmetries in fat score and asymmetries in body size within age were related to dominance status in dyadic trials, whereas asymmetries in body size and asymmetries in fat score within age were related to dominance status in group trials. Therefore, it seems that resource value or winner-loser effects may motivate fighting in dyads whereas fighting ability becomes more important in groups. Our results have to be considered in the design of future studies, as differences in social environment may have important implications for the outcome of trials.