Red squirrel protection methods 'could be better'
One report, from Forestry and Land Scotland (FLS), the University of the Highlands and Islands (UHI) Inverness and Heriot-Watt University, indicates that red squirrel populations are viable in landscapes managed for timber and that current special protection measures are ineffective and should be relaxed.
FLS's wildlife ecologist Kenny Kortland said the latest research shows that commercial forestry "isn't a threat to red squirrels" and that, when managed carefully, forestry plantations "can be great habitats for red squirrels".
"Work that UHI has done over the past five years to track squirrel movement before and after thinning operations found no detrimental impact on red squirrel breeding activity or survival," he said.
"In fact, population density was higher after the operations.
"The only measurable impact was a slight shift in space use for a couple of individual squirrels, which was likely due to food availability.
"This suggests that there are probably better management tactics from both the forester and the squirrel's point of view."
He said the £100,000 upwards that is currently spent annually on red squirrel management measures could be more effectively channelled to other conservation efforts.
The study also found conservation work on red squirrel strongholds, which is currently focused on areas where greys are absent, would be more effective in areas where grey squirrels pose a danger, such as south of the central belt or in lower Tayside.
The stronghold forests have been altered - by removing or not planting the broadleaf species preferred by greys - to favour red squirrels and prevent greys from moving in.
But research done by Professor Andy White, a mathematical ecologist at Heriot-Watt University, and internationally recognised squirrel expert Dr Peter Lurz questions whether focusing on these areas is an effective strategy.
Prof White said: "Many of the current 19 strongholds are in regions where the greys are absent.
"So the time and money spent modifying these forests to better prepare reds for the impacts of grey competition may have little additional benefit.
"Even in a worst-case scenario of grey squirrel invasion, there are large forested regions where the tree species present would support the reds but would be unfavourable to greys."
He added: "It does suggest that the stronghold programme would be more effective if it were adapted to where greys pose a danger, such as south of the central belt or in lower Tayside."
Tree-felling operations often result in members of the public contacting forest managers with concerns about the impact on their local red squirrels.
Currently, operations in important squirrel forests are scheduled to avoid the breeding season and felling work will often be postponed if pre-operational surveys find dreys - the nests of squirrels.
Site-specific mitigation can include retaining drey trees and felling in such a way as to make it as easy as possible for squirrels to relocate into adjacent crops.
But Dr Louise de Raad, formerly a research fellow at UHI Inverness, said drey surveys are not effective.
She said: "Since 2017, FLS and UHI Inverness have been studying how red squirrels respond to tree felling by fitting squirrels with radio collars and tracking their movements before, during and after the tree-felling work.
"When we combined the tracking results with drey survey returns we found that the survey missed over 80% of dreys that were actually used by red squirrels.
"It's clearly not an effective mitigation to leave identified drey trees and it would be better to focus on other methods - such as looking for signs such as chewed cones, for example - that only indicate the presence or absence of red squirrels in a forest."
She added: "We must continue to protect red squirrels, but we need to review the current mitigation strategies to make sure we do this in the most effective way."