YOUR enemy鈥檚 enemy is your friend. The UK鈥檚 endangered red squirrels are getting an unexpected helping hand聽鈥� from predators that kill the grey squirrels that threaten them.
are native to North America. They got settled in the UK in the 19th century after being brought over by a silk manufacturer, and soon began to suppress the native . They are bigger, bolder and eat a more varied diet, and also carry a virus deadly to red squirrels. Today, they have driven red squirrels out of much of the UK聽鈥� although in Europe .
It has been suggested that predators called pine martens , by driving down grey squirrel populations.
Advertisement
look like a cross between an otter and a weasel. They were almost wiped out in the UK, but have been recovering since the 1970s.
Emma Sheehy at the University of Aberdeen, UK, and her colleagues studied the populations of all three animals in Scotland during 2016. They enticed pine martens and squirrels to feeders and recorded their numbers, using DNA analysis and cameras.
This revealed how often red and grey squirrels encountered pine martens, and how this affected them.
In areas where grey squirrels were exposed to pine martens, their numbers dwindled, whereas red squirrel numbers increased if they encountered pine martens ().
Red squirrels were more cautious than grey squirrels when visiting feeders in areas with lots of pine martens, says Sheehy. It may be that grey squirrels don鈥檛 recognise pine martens as a threat, as they didn鈥檛 evolve alongside them, she says.
Sheehy鈥檚 team is now studying how the growing pine marten population is affecting farmers and foresters, who have persecuted them in the past.
This article appeared in print under the headline 鈥淧ine martens may save UK鈥檚 red squirrels鈥�
