SquirrelWeb

The All-Ireland Squirrel and Pine Marten Survey 2019 has been published by the National Parks and Wildlife Service. The findings are encouraging. For example, pine marten sightings have increased over the last seven years and their core range has expanded from the west and midlands to County Wicklow and Northern Ireland. At the same time, the range of the grey squirrel has decreased or disappeared in some areas with a commensurate increase in red squirrel sightings. However there was some evidence that the grey squirrel had moved into the southwest and they are still abundant around Belfast and Dublin. Moreover, recent research by Josh Twining and colleagues from Queen’s University, Belfast suggest that even if grey squirrels were forced out of all rural areas allowing red squirrels to return, pine martens do not inhabit urban areas where grey squirrels would continue to thrive. These urban refugia would allow grey squirrels to continuously push into rural areas and eventually they could develop strategies enabling them to evade the pine marten so again putting red squirrels at risk. (The Guardian; Journal of Applied Ecology)

According to the Portugal Resident publication, red squirrels in  Portugal are being killed by a strain of adenovirus found in South Korea. Scientists are trying to establish how this has occurred.

The latest survey of red and grey squirrels in Scotland indicates that numbers are stable with some minor regional changes and some optimism for the future. Further details can be found in: The National, The Canary, The Herald.

Joshua Twining and colleagues from Queen’s University Belfast have recently published a study in Royal Society Open Science that shows that red squirrels are better than grey squirrels at detecting the scent of pine martens. This may be one reason why alien grey squirrels tend to ‘disappear’ when pine martens move into an area, whereas red squirrels, which have evolved alongside pine martens, are able to behaviourally respond and avoid the danger. This favours the return of red squirrels to areas where they had previously been replaced by grey squirrels (see BBC News, Yahoo News, The Irish Times, RTE, Irish Mirror, The Scotsman).

Lisa Leaver and colleagues at Exeter University have studied whether grey squirrels are left-handed or right-handed in laboratory tests. Many squirrels appeared to favour their left or their right paw, but these squirrels performed less well than those which were ambidextrous. The studies, which will be published in the scientific journal Learning and Behaviour, contribute to the debate about lateralisation and cognitive performance. (Belfast Telegraph, Metro, Sun, BBC Science Focus, Exeter University)

The Roslin Institute in Edinburgh is spearheading a study to edit the genes of male squirrels to contain a gene-drive that, once the males are released, should quickly spread throughout the population and make future females sterile. The idea is that the spread of female infertility in the population will mean the population is unable to replace itself and be eliminated. The project, partly funded by the European Squirrel Initiative, is believed to be a humane way of reducing grey squirrel numbers, although opposition has come from animal rights campaigners and animal ethicists (The Scotsman, Express, The Times, Front Line Genomics).

An unconfirmed case of a red squirrel with squirrelpox virus disease at Smardale Nature Reserve, Cumbria was reported by a Cumbria Wildlife Trust volunteer. The virus is carried by grey squirrels and the disease it causes in red squirrels is invariably fatal. Local people and volunteer groups are being asked to be vigilant and sterilise bird feeders where necessary (KentLive, The Westmorland Gazette)

Over 600 people took part in the first Great Scottish Squirrel Survey which was carried out from 23-29 September this year. Greys were reported 198 times and red squirrels 630 times. These valuable findings provide insights into how red squirrels are faring in different parts of the country and the efforts of many people in trying to save the red squirrel. The Herald provides a good account of the achievements of the survey.

Trees for Life have embarked on their latest phase to reintroduce red squirrels across the Scottish Highlands by translocating 20 animals from Inverness-shire and Moray to Ledmore and Migdale Woods in Sutherland. Red squirrels were present in these areas until about 20 years ago and critically grey squirrels are absent (The Scotsman, The Herald).

People interested in wildlife in general and squirrels in particular will be closely following the progress of pine martens recently introduced into the Forest of Dean in the counties of Gloucestershire, Herefordshire and Monmouthshire. Eighteen martens were moved from Scotland to the Forest of Dean by Forestry England, the Gloucestershire Wildlife Trust, the Vincent Wildlife Trust and Forest Research and fitted with radio-collars before release. Few pine martens are thought to be currently present in England, but more than 50 pine martens were successfully released into Wales between 2015 and 2017. Over the years the non-native grey squirrel has caused a great deal of damage to trees in the Forest of Dean and elsewhere. There is evidence from Ireland and Scotland that the number of grey squirrels in an area decline when pine martens move in. Thus we wait and see what will happen to the grey squirrel population once the pine martens become established. (BBC News, The Independent, PA Media, Evening Express, The Guardian, The Canary, Shroud News)