When to count? Indices of population size for mountain hares of the north-west Lammermuir Hills, Scotland

Abstract

Surveys with binoculars at two different times of day and in various months of the year, along with camera trap studies of diel activity patterns, were used to inform an appropriate period to count mountain hares ( Lepus timidus) on managed red grouse (Lagopus lagopus ) moorland of the Lammermuir Hills, south-east Scotland. Factors affecting the numbers of hares counted were time relative to sunrise, the presence of winter coat colour and reproductive behaviour in spring. Counts of hares in March and April starting one hour before dawn were used as an index of population size of the mountain hare over three years of observations on three hill-tops, with densities of 23-33 hares km-2. The number of hares seen was stable or rose slightly over the three years despite a partial cull on one of the hills. In support of suitability of the timing of surveys used, camera trap studies revealed that the period around dawn in March and April was associated with high levels of hare activity.