Density and productivity of breeding Skylarks Alauda arvensis in relation to crop type on agricultural lands in western France

Capsule Small field size and the maintenance of set-aside and lucerne are important to ensure high breeding pair densities and productivity. Aims To investigate the effects of crop types and their attributes on density and productivity of breeding Skylark. Methods At each of four selected study sites in western France, territory density, vegetation height, vegetation cover and field size was estimated by field and attempts were made to find nests. Crop types included winter and spring cereals, oilseed rape, sunflower, maize, grass, lucerne, set-aside, and bare ground. Results About 80% of Skylark territories included more than one crop type. Birds preferred small fields and territory density decreased with increasing field size. Density was highest in crops with low vegetation height and cover. Set-aside, lucerne and grass supported highest territory density. Fledging productivity was highest in set-aside and lucerne, and was zero on bare ground. Skylark density decreased throughout the breeding season (-26% in 1999 and -29% in 2000), suggesting an instability in territory distribution or activity in intensive farmland. Conclusions Farming systems that decrease field size and increase set-aside and lucerne instead of oilseed rape, maize and sunflower will benefit Skylark and other declining farmland species.