How nesting support type interacts with vegetation greening and distance to nest trees of mixed-species to predict white stork nest density in a Mediterranean capital

Abstract

White Stork (WS) ( Ciconia ciconia (Linnaeus, 1758)) ranks among the most common breeding birds in many Mediterranean cities, underscoring the importance of studying nest densities, particularly when populations are increasing. In this study, conducted in Rabat (Morocco), we aimed to investigate the effects of coloniality, landscape composition, and space to identify the best predictors of variation in the number of WS nests per nest support using generalized linear mixed models. The results revealed significant interactions between the type of support (trees vs. pylons) and normalized difference vegetation index (NDVI) as well as between the support type and the distance to the nearest support occupied by WS and Cattle Egret (CE) ( Bubulcus ibis (Linnaeus, 1758)) nests. A high number of nests are associated with an NDVI increase around pylons, while such an effect is insignificant around trees. In contrast, a high number of WS nests are noted close to supports occupied by both WS and CE nests, whereas in pylons, this number is recorded far away from them. The implementation of a scientific monitoring system is crucial for determining, at a defined time step, the direction and strength of relations between WS and CE populations in Rabat.