The diet of stoats (Mustela erminea) and weasels (Mustela nivalis) in Great Britain

The diet of 789 stoats Mustela erminea and 458 weasels M. nivalis collected in Great Britain between 1995 and 1997 is described from analyses of their gut contents. As a percentage frequency of occurrence, stoat diet consiste d of 65% lagomorphs, 16% small rodents and 17% birds and birds' eggs. Wease l diet consisted of 25% lagomorphs, 68% small rodents, mainly Microtus agre stis, and 5% birds and birds' eggs. Male stoats ate a greater proportion of lagomorphs than females, which ate more small rodents. No differences in d iet between the sexes of the weasels were detected. The proportion of lagom orphs in the diet of both species was greatest in the spring. Both species ate more lagomorphs in the 1990s than in the 1960s as a result of increasin g rabbit populations following recovery from myxomatosis. The importance of small rodents had decreased for stoats and increased for weasels. Both spe cies had a dietary niche that was more specialized than in the 1960s. The i mplications of these findings for stoat and weasel conservation are discuss ed.