• Key words.;
  • Butterflies;
  • pesticides;
  • farmland;
  • conservation headlands

Abstract. 1. On a study farm in Hampshire where large blocks of cereal fields had the pesticide inputs on their headlands experimentally and selectively reduced (the practice known as ‘conservation headlands’), numbers of butterflies were monitored over 4 years by using transect counts.

2. Consistently more butterflies were seen flying over field edges sprayed under the conservation headland regime compared to those that were fully sprayed.

3. A comparison of changes in butterfly abundance on the study farm containing conservation headlands with data from the National Butterfly Monitoring Scheme indicated that population increases in some species may result from the use of conservation headlands.

4. The implications of resource provisioning and the potential reduction of spray drift into field-margin habitats are discussed in relation to farmland butterflies.