Agricultural land use shapes habitat selection, foraging and reproductive success of the Lesser Spotted Eagle Clanga pomarina

Abstract

Anthropogenic loss of biodiversity is often indicated by the disappearance of top predators. However, some of them have adapted to man-made agricultural landscapes. Among raptors, one such example is the Lesser Spotted Eagle. We compiled an exhaustive data set on foraging habitat composition of this species by direct field mapping and detailed land cover maps to study the effect of various agricultural management practices on its occupancy of home ranges and productivity, as well as on its habitat utilization and hunting success. Home ranges of the Lesser Spotted Eagle contained more natural grasslands (7.6%) and other agricultural biotopes (29.9%) than expected by random, and they preferred to breed close to managed agricultural biotopes. They hunted preferably on grasslands, where they spent 86% of their time, especially on managed grasslands, but avoided arable fields. In total, 51% of the Lesser Spotted Eagle attacks were successful, and we detected no differences in hunting success among habitats. Nests of successfully breeding birds were surrounded by more crops/cultivated grassland on a rotational basis (19.0%), as well as by managed natural grassland (1.1%), than those of unsuccessful pairs (16 and 0.7%, respectively). We also detected a negative impact of oilseed rape fields and mowed cultivated grassland on the reproductive success of the Lesser Spotted Eagle, but these effects were not consistent over the years. Our results suggest that, although the Lesser Spotted Eagle is well adapted to foraging in traditional farmland, it is threatened by changes in agricultural practices and an increasing sown area of some crops, such as oilseed rape. Cultivation of various crops and retaining of grasslands, interspersed with set-aside and non-agricultural habitat patches, promoted by the European Union greening policy, would be favourable to the Lesser Spotted Eagle.