Prospectors combine social and environmental information to improve habitat selection and breeding success in the subsequent year

Abstract

1. Because habitats have profound effects on individual fitness, there is strong selection for improving the choice of breeding habitat. One possible mechanism is for individuals to use public information when prospecting future breeding sites; however, to our knowledge, no study has shown prospecting behaviour to be directly linked to subsequent choice of breeding site and future reproductive success. 2. We collected long-term data on territory-specific prospecting behaviour and subsequent breeding in the short-lived northern wheatear (Oenanthe oenanthe). Non-breeders established prospecting territories (<2 ha) that overlapped the breeding territories of conspecifics. We tested whether: (i) prospectors used social and environmental cues that predicted territory-specific breeding success in the following year, and (ii) the prospecting territory was tightly linked to the subsequent breeding territory of the prospector, and whether this link would be weakened by intraspecific competition with original territory owners if they also survived. 3. As expected, prospectors were attracted to a combination of site-specific cues that predicted future breeding success, i.e. short ground vegetation, a successfully breeding focal pair and successful close neighbours. 4. Prospecting behaviour was directly linked to the choice of the following year's breeding territory: 79% of surviving prospectors established a breeding territory at their prospecting site in the following year, with their breeding success being higher than other individuals of the same age. As predicted, fidelity to the prospected site was strongly dependent on whether the original territory owner of the same sex had died or moved. 5. Our findings suggest that the use of multiple cues reduces the negative impact of stochasticity on the reliability of social cues at small spatial scales (e.g. territories) and hence increases the probability of breeding success in the next year. Also, the use of conspecific attraction (i.e. the preference for breeding aggregations) is selectively advantageous because individuals are more likely to find a vacancy in an aggregation as compared to a solitary site. By extension, we hypothesize that species life-history traits may influence the spatial scale of prospecting behaviour and habitat selection strategies.