Do voles make agricultural habitat attractive to Montagu's HarrierCircus pygargus?

Abstract

Loss and degradation of habitat threatens many bird populations. Recent rural land‐use changes in the Netherlands have led to a shift in habitat use by breeding Montagu's HarriersCircus pygargus. Since the 1990s, unprecedented numbers of this species have bred in farmland compared with numbers in natural habitat. Destruction of nests by agricultural operations, however, compromises breeding success. Between 1992 and 2005, the number of breeding pairs in the northeastern Netherlands was positively, though weakly, correlated with previous‐year estimated abundance of voles, mostlyMicrotus arvalis. In good vole years, the onset of laying was earlier and mean clutch size was larger. Vole abundance was relatively higher in set‐aside land and in high and dense vegetation. We suggest that agri‐environmental schemes aimed at increasing the availability of voles in agricultural breeding areas may be an effective management tool for the conservation of Montagu's Harriers in the northeastern Netherlands.