Weasel and stoat populations have not been falling as steeply as had been feared.
Robbie McDonald and Stephen Harris of Bristol University report in the Journal of Applied Ecology that previous population estimates have been erroneously based directly on gamekeepers' kill records.
A survey of 203 English gamekeepers found the trend towards hand-rearing game birds meant less effort was being put into trapping and shooting weasels and stoats.
accurately reflect true population levels when this is taken into account, Dr McDonald said.
"It looks like stoats may even be increasing in number on game estates, while weasels may be declining only slightly," he said.