Summer bird abundance and distribution on set-aside fields on intensive arable farms in England

The abundance and distribution of breeding birds were compared on paired fi elds comprising one set-aside Bald and one crop field, on 11 intensive arab le farms in eastern and western England. A single observer made four visits to all set-aside and clop fields between April and July and recorded all b irds seen during standardised counts and transects. Rotational and non-rotational set-aside supported higher densities and more species of birds than fields of wheat, brassicas, root crops and seed rye. These differences in density, between set-aside and crops, were evident ac ross a suit of species including waders, gambirds, pigeons and passerines a nd were particularly marked on rotational set-aside. The majority of specie s recorded in fields away from boundaries would have been feeding rather th an nesting there and higher bird densities on set-aside compared with adjac ent arable crops probably reflects greater food abundance in the former. The study is the first to demonstrate a clear habit preference for set-asid e by a wide range of bird species throughout the breeding season and it all ows a number of recommendations to be made concerning the development of co st effective agri-environment measures. The fact that the majority of birds utilised the outer 5 m, or in some cases 20 m. margin of the field suggest s that many of the benefits of whole held set-aside may be derived from mar ginal strips. A slight, but not significant preference for rotational over non-rotational set-aside suggest such margins should be managed to maintain a patchy, relatively diverse sward of arable plants. A key feature of set- aside is the scale at which it has been incorporated into the arable landsc ape. Agri-enviromental schemes will only provide similar national benefits if they are implemented on a wide scale in such as way as to promote high u ptake by farmers.