Agricultural intensification and the timing of breeding of Corn Buntings Miliaria calandra.

Abstract

Capsule In an intensively managed agricultural landscape, few females attempted a second brood.
Aims To investigate the effect of modern farming practices on the number of Corn Bunting breeding attempts.
Methods We compared the timing of breeding by Corn Buntings on the South Downs, West Sussex, with the habitat composition within 150 m of their nests.
Results Breeding was earlier in areas containing winter-sown wheat and set-aside than in areas containing spring-sown barley. Nests were earlier when cereal crops near the nest were more developed. The presence of unripe grain was a better predictor of the timing of breeding than the height of the crop. Double-brooding was extremely rare and few females re-laid after nest failures. Daily failure probabilities of clutches increased during the season, largely as a result of harvesting operations.
Conclusions Changes in the timing of cereal harvesting and the availability of uncultivated nesting habitat may have reduced the incidence of double-brooding in some intensive arable landscapes. Food availability may also limit the onset of breeding, further reducing the possibility of double-brooding.