Allocating active conservation measures using species distribution models: a case study of red‐footed falcon breeding site management in the <scp>C</scp>arpathian <scp>B</scp>asin

Abstract The red‐footed falcon F alco vespertinus is an enigmatic colonial raptor of high international conservation concern. One of the identified threatening factors responsible for the recent worldwide population decline is the shortage of suitable colonial nesting sites. In theory, this problem can easily be resolved by establishing artificial colonies. However, the key to a successful large scale nest‐box scheme is to provide these artificial colonies in habitats suitable for the species. A H ungarian– S erbian project aimed to establish such nesting facilities in northern S erbia, although the lack of recent full‐scale habitat surveys hindered the designation of the locations of these artificial nesting sites. We used five different species distribution models to model the distribution of nest sites on a 10 × 10 km grid in H ungary and in R omania. We then used the ensemble predictions of the best performing models to project the probability of red‐footed falcon nest site presence in northern S erbia (predicted area). The models showed that three variables (grasslands, pastures and broad‐leaved forests) had the highest importance in describing the spatial pattern of nest sites in the modelling area. The extent of grasslands and pastures had positive effects, while broad‐leaved forests had negative impact on the probability of nest site presence. The predictions classified all the currently known colonies in the predicted area correctly. Our results suggest that the potential breeding distribution in S erbia is similar to that of two decades ago, thus large‐scale land use changes are presumably not responsible for the reported population decline. We have also reduced the extent of conservation target areas to 11.5%, allowing to pinpoint locations for these future nest box colonies, and also provided a basis for future conservation measures like allocating monitoring efforts and designating future N atura 2000 sites in S erbia.