Influence of landscape and land-use on the distribution of breeding birds in farmland in eastern England

The relationships between landscape, land-use and the number of territories of eight species of birds, most with declining populations, were studied o ver 3 years in an area of largely arable agriculture in eastern England. Tw o species, skylark. Alauda arvensis and yellow wagtail Motaeilla flava, est ablished territories within crops. More than half of skylark territories we re in autumn-sown cereals, but densities were higher in set-aside and sprin g-sown crops, while a conservation grassland cut for hay in late July held the highest density. Skylarks did not switch territories in winter cereals for other crops as the breeding season progressed. Weak preferences were fo und for spring-sown crops and weak avoidance of autumn-sown crops (i.e. the re were fewer territories than expected from the area under autumn-sown cro ps). Skylarks showed preferences for set-aside and conservation grassland b ut other grassland was avoided. Skylark numbers were negatively associated with hedgerow length within tetrads. Most yellow wagtails nested in spring- sown crops, especially potatoes, for which there was a strong preference; m ost territories were in the largest fields. More than 75% of territories of turtle dove Streptopelia turtur. were associated with residential areas, s crub and woodland, with hedges used much less often than expected from thei r occurrence. Grass was a strongly preferred land-use. Linnets Carduelis ca nnabina were mainly located in small areas of scrub and there was an associ ation with winter oil-seed rape. Common whitethroats Sylvia communis showed preferences for hedges, especially for tall hedges, though many territorie s were situated in field boundaries with only scattered shrubs. Lesser whit ethroats S. curruca preferred only tall hedges. Both species had more terri tories adjacent to grass than expected, with common whitethroat also showin g a preference for winter oil-seed rage. Yellowhammers Emberiza citrinella declined over the 3 years of the study. Territories were strongly associate d with tall hedges, but preferences for crops were weak. The small number o f reed bunting E, schoeniclus territories were almost all by water, with a preference for adjacent grass. Possible mechanisms for It versing the downw ard trends of bird populations on farmland are discussed.