Grey squirrel predator lets reds flourish

RED squirrels are receiving an unlikely boost to their numbers – from a predator.

The pine marten is killing grey squirrels as it recolonises the Scottish Borders, but reds are thriving. This may be because they avoid pine martens – members of the weasel family – after evolving alongside them. They have flourished as pine martens kill greys, which infect reds with pox and take their food.

The University of Aberdeen recorded the phenomenon in a report titled ‘The enemy of my enemy is my friend’ in the journal Proceedings of The Royal Society B.