Clutch size and egg size in the breeding strategy of Montagu's Harrier Circus pygargus in a Mediterranean area

First-summer set-aside fields held more breeding species and higher wader densities than in the previous summer. They held more breeding species and higher densities of waders, Partridges (Perdix perdix) and Skylarks (Alauda arvensis) than fields in crop. Mowing nullified many breeding attempts. Corn Buntings bred in some first-summer set-aside fields but numbers were lower in other cases. Later years of set-aside held lower densities and fewer species. Densities of waders and Partridges in first-summer set-aside exceeded those in the first year of resumed cropping.