Intra-guild spatial niche overlap among three small falcon species in an area of recent sympatry

Climate warming and land-use change are reshuffling the distribution of wild organisms on a global scale. Some species may expand their ranges colonize new regions, which greatly affect ecological interactions among pre-existing colonizers. In last decades, such processes have originated unique condition sympatry three Eurasian small Falco (common kestrel F. tinnunculus, lesser naumanni, red-footed falcon vespertinus) in intensively cultivated farmland habitats Po Plain (Northern Italy). This provides an excellent opportunity to investigate patterns spatial niche overlap during initial phases establishment sympatry. To species, we relied Environmental Niche Models (ENMs) based widespread breeding occurrence data obtained through field surveys citizen science programs (during 2018–2020 period). ENMs were bioclimatic variables ensemble modelling framework. We estimated species-specific relative contributions each climatic variable its response curves effect. Eventually, generated correlation maps potential species’ distributions derive spatially-explicit predictions co-occurrence areas species. Overall, eco-climatic determinants similar, resulting strong association with intensive arable lands dry continental climate. Consistently, found high between suitability two highly suitable located Central-Eastern area Plain, corresponding core range both Conversely, common emerged as habitat generalist was widely distributed throughout Plain. Our findings suggest that recent kestrels falcons promote intra-guild competition.