Habitat preferences and breeding success of Whinchats (Saxicola rubetra) in the Westerwald mountain range

摘要

The Whinchat (Saxicola rubetra) has experienced dramatic population declines in central Europe over past decades. To support evidence-based conservation strategies, we have analyzed habitat preferences, breeding success, and population development inselected study sites within the Westerwald mountain range, representing a major stronghold of Whinchats in Germany. Whinchat territories were characterised by higher proportions of pastures and nutrient-poor moist grassland than expected by chance, and they showed higher levels of ground unevenness, higher numbers of perches, higher structural vegetation diversity and greater distances to forests than control patches. Breeding success differed significantly across biotope types, being highest on nutrient-poor moist grassland followed by nutrient-poor (but drier) grassland, fallow land, and finally nutrient-rich grassland. It also depended on the timing of grassland management. In the study site with traditional grassland management, breeding success was 82 %, while it was only 38 % in an intensively managed study site. Accordingly, the local population size declined between 2005 and 2011 from 48 to 5 singing males in the intensively managed site, but 'only' from 51 to 31 singing males in the traditionally managed site. In our study area, Whinchats can only produce high offspring numbers if grazing and mowing does not start before 1 July, and preferably not before 15 July.