Effects of temporal factors, nesting microhabitat and nest position on the survival of passerine nests in a Tunisian oasis habitat§

Abstract

Identifying the ecological factors shaping bird nest survival is essential for understanding bird population dynamics, as well as for conservation purposes. Using data obtained by monitoring natural bird nests in one oasis in south-eastern Tunisia, we fitted logistic exposure models to investigate the effects of nesting microhabitat, nest position and temporal parameters on nest survival rates. Nest age was the most important predictor of daily nest survival rate for the five focal species. However, contrary to many previous studies, daily nest survival rate was positively related to nest age. This finding could be explained by the fact that the main nest predators in Tunisian oases are rodents that are more likely to consume eggs rather than chicks and therefore their impact on bird nests is assumed to be higher during incubation than after hatching. Nesting microhabitat variables and nest position as well as date of nest initiation and year did not significantly affect bird nest survival in the studied oasis. Further studies on the ecology and behaviour of nest predators are needed to more accurately identify the determinants of bird nest survival in the oasis habitat.

Keywords: logistic-exposure model, nest age, nest survival, oasis, passerines