Predation of Pied Avocet Recurvirostra avosetta nests in a salina habitat: Evidence for an edge effect

Abstract

Capsule The edge effect hypothesis of nest predation in habitat patches and colonies is supported Aims To test whether nest predation rates in Pied Avocet colonies are a function of distance from the colony edge. Methods The study was conducted in Sfax salina (3439'N, 1042'E) in Tunisia. We monitored Pied Avocet nests in 30 colonies established at different distances from the salina-suburbs edge. Using the Mayfield method, we estimated nest predation rate in each monitored colony. Regression analyses were used to investigate the relationship between nest predation rate and distance from colony edge. Results Predation by stray dogs coming from Sfax suburbs was responsible for the failure of a significant number of monitored nests. Nest predation rate varied among colonies and was found to be negatively correlated with distance to salina-suburbs edge. Conclusion The results support the edge effect hypothesis. Pied Avocet colonies located near the edge between Sfax salina and the suburbs of Sfax city suffered higher predation rates than those situated in the salina interior. The installation of fences separating the salina from Sfax suburbs is likely to promote the nesting success of waterbirds in this important bird-rich habitat. © 2011 British Trust for Ornithology.