Mate and territory availability affect breeding dispersal and divorce in a resident Southern House Wren Troglodytes aedon musculus population

Abstract

Breeding dispersal is the movement of an individual between breeding attempts and is usually associated with the disruption of the social pair bond, although mates may disperse together as a social unit. In monogamous territorial species, the decision to disperse may be affected by individual attributes such as sex, age and condition of the disperser. However, environmental and social contexts may also play a crucial role in the decision to disperse. We analysed capture-resighting data collected over 9 years to study breeding dispersal and divorce rates of a Southern House Wren Troglodytes aedon musculus population in South Temperate Argentina. Between-season dispersal was more frequent than within-season dispersal, with females dispersing more often than males, both between and within seasons. Both within-season and between-season breeding dispersal probability was affected by territory availability, but not by previous breeding success. When the adult sex ratio (ASR) was more skewed towards males, male between-season dispersal was also affected by mating status, with widowed and single males dispersing more often than paired males. Within-season divorce increased the reproductive success of females but not males, and was affected by the availability of social partners (with increasingly male-skewed ASR). Our results suggest that territorial vacancies and mating opportunities affect dispersal and divorce rates in resident Southern House Wrens, highlighting the importance of social and environmental contexts for dispersal behaviour and the stability of social pair bonds.