Diurnal and nocturnal ranging behaviour of Stone‐curlews Burhinus oedicnemus nesting in river habitat

Abstract

Studying a species under a range of conditions is essential for fully understanding its ecology and for predicting its response to human impacts on the environment. We investigated the spatial behaviour and the habitat characteristics of foraging areas of Eurasian Stone‐curlews breeding in an important but poorly investigated habitat, gravel riverbed, throughout the full 24‐h cycle. The data collected for 17 radiotagged birds nesting in the Taro River Regional Park (Parma, Italy) showed a clear split between diurnal and nocturnal spatial behaviour. Almost all diurnal fixes and about two‐thirds of nocturnal ones were located in the gravel riverbed, which not only provided suitable breeding territories but probably part of the food resources needed for reproduction. Nocturnal excursions from breeding sites to feeding areas (mostly farmland), sometimes of a few kilometres, indicated that these resources do not cover all of the birds’ needs. Night spotlight counts of foraging birds in the agricultural area indicated that Stone‐curlews preferred recently harvested crops (mainly forage and wheat) and piles of farmyard manure. These habitat preferences are closely linked to the predominant agricultural activity of the study area, which is characterized by a high density of dairy farms for the production of Parmigiano Reggiano cheese. It seems likely that the proximity of gravel riverbed and farmland habitats is one of the main causes of the high breeding density recorded in the study area. We propose that the conservation of Stone‐curlews at this site could potentially be achieved only by a synergistic management of both natural and agricultural habitats.