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.

Highest densities of mountain hares (Lepus timidus) associated with ecologically restored bog but not grouse moorland management

“…That said, we had deliberately chosen those areas for survey efficacy. By contrast, in mountain hare surveys on the Scottish Lammermuir hills, Pettigrew ( 2020 ) recommended 90‐min surveys by dawn light as hares are more active and visible at this time rather than by midday when dormant. However, this suggestion lacked information regarding imperfect detection process or detection probability so is hard to compare; and those surveys occurred on small accessible areas ~26 km 2 of relatively flat elevation 420–520 m. By contrast, the Peak District required >120 km of transects and featured steep hills elevation 630 m with transect elevation changes >350 m over 1 km.…”

The diel activity pattern of mountain hare (Lepus timidus) on managed heather moorland in Scotland

“…The general topography of the study area, the pattern of muirburn (Yallop et al., 2006), and the location of camera traps are shown in Figure 1b. During mountain hare surveys (Pettigrew, 2020), up to 20 individual hares have been routinely counted by the Lammermuir Hare Group in the camera study area.…”

“…The general topography of the study area, the pattern of muirburn (Yallop et al, 2006), and the location of camera traps are shown in Figure 1b. During mountain hare surveys (Pettigrew, 2020), up to…”

“…Counting mountain hare is much easier when they are active. Using part of the same dataset presented here, one of us has explored how activity studies can inform the best time of year and the best time in the 24‐hr cycle to count (Pettigrew, 2020): this at a time when there is controversy surrounding uncontrolled culling (Brooker et al., 2018).…”