Heterogeneity of crop mosaic was not important in explaining occurrence of Lesser Kestrel. In contrast, irrigated crops negatively influenced occurrence. The best AIC-based models explaining occurrence of Lesser Kestrels showed that fallow was the more important habitat type followed, to a lesser extent, by dry cereal stubble and field margin. To analyze Lesser Kestrel occurrence, we used generalized linear models, a theoretic-information approach and a hierarchical partitioning analysis. In this study, we examine the role of fallow in fine-grained habitat use by a threatened farmland bird (Lesser Kestrel) during summer in northwestern Spain. However, the obligatory set-aside has recently been abolished by the Common Agricultural Policy Health Check. These are mainly introduced as part of both obligatory and voluntary set-aside schemes. The maintenance of fallows has been shown to prevent the loss of farmland biodiversity caused by agricultural intensification.
