Abstract
The diet of kestrels was investigated in the southern uplands of Scotland [UK] from 1976-1979 by analyzing 1414 pellets and recording 890 prey items at nests. Voles were the most frequent prey and the occurrence of other items was apparently related to their abundance relative to voles. Some items such as birds and earthworms underwent fluctuations in the diet that were related to seasonal changes in their availability to kestrels. Prey other than voles was more frequently recorded in poor vole years than in good ones, and more often in sheepwalk than in young conifer plantations. Pellets composed entirely of voles were heavier in good vole years than in poor ones, suggesting that kestrels unable to find alternative food may have had a reduced food intake when voles were scarce.