Contrasted habitat selection among Eurasian curlew populations according to landscape heterogeneity and breeding stage

Abstract Since the late 1970s, European landscapes have been severely degraded by the intensification of agricultural practices that replaced the historical mosaic of natural and agricultural environments with an increasingly uniform landscape. This homogenization of the mosaic structure has led to a depletion of available resources for farmland birds, resulting in a decline in their populations. This study aimed to quantify the relationships between spatial landscape heterogeneity and the spatio‐temporal use of breeding habitats by Eurasian curlews ( Numenius arquata ) in contrasting agricultural landscapes. From 2020 to 2024, we tracked 64 adult curlews with global positioning system tags in 5 breeding sites with contrasting population dynamics in France (i.e., 2 declining, 2 increasing, and 1 stable). We assessed variations in home range size and habitat use according to breeding stage (i.e., pre‐incubation, incubation, chick rearing, pre‐migration), and assessed foraging habitat selection. Home ranges were small and did not differ in size among sites (mean ± SD = 97.4 ± 43.6 ha), although the nature of the nesting environment and its distance from other nutritional environments influenced the fragmentation of individual space use. In all sites, curlews selected to forage in open areas. They preferentially used grasslands for nesting and foraging, except in a drastically declining population, wherein all remaining birds nested in moorlands. Additionally, curlews increasingly used crops after incubation, potentially to supplement their resources before migration. This study's findings also highlight the importance of floodplain grasslands for maintaining Eurasian curlew populations, although a landscape structure with sustainable agricultural land embedded in semi‐natural lands may also be beneficial to their populations.