Survey of the Tayside area beaver population 2017-2018

Main findings
– Beaver activity was recorded throughout large parts of Tayside.

– Beavers are spreading in distribution and are present outside the catchments of the Tay and Earn. Small numbers of territories occur within the Forth catchment from Loch Achray in the Trossachs, parts of the Teith and Devon, and the main stem of the Forth near Stirling.

– No evidence of beaver presence was found on the South Esk nor in several freshwater bodies associated with the lower Forth and Forth estuary, including Loch Leven.

– Distribution in Tayside ranged from as far north as Dunalastair Water, extending out to the River Dochart and River Lyon in the west, over to Forfar Loch in the east and down to Loch Earn in the south.

– 114 active beaver territorial zones were identified in this study, giving a conservatively estimated number of approximately 433 beavers (range 319 – 547). This number is based on a previously reported European mean group sizes of 3.8±1.0 animals per territory, which was also used in the 2012 SNH survey. Some identified zones may constitute multiple families and additional active territories, along with dispersing singletons, are likely to exist both within Tayside, especially on minor watercourses, and outside of the Tayside catchment which it was not feasible to cover during this survey.

– Out of the 114 beaver territories defined using the 2017/2018 survey data, 100% were contained within the areas identified as ‘Potential Beaver Woodland’ and 95% were contained within the ‘Potential Core Beaver Woodland’, as defined by previous SNH GIS mapping exercises (Stringer et al. 2015).

– Potential management issues were recorded at a total of 159 points, across 21 territories, ranging from dam building, collapsed burrows, tree felling, crop feeding and damage to fence lines.

– A total of 86 dams, or sites where dams had been removed, were recorded. Of these, 41 dams occurred within one private estate.

– There was an increase in both beaver distribution and density compared to the 2012 survey although spatial variability was evident, with areas of expansion and infilling, along with smaller areas of habitat abandonment potentially through culling.