Grey squirrels do not fully deserve their reputation as dastardly woodland invaders, a study has found.
Genetic research has shown they have been unjustly accused of driving out red squirrels like an invading army.
In fact they were imported into the UK from North America in the 1800s and spread rapidly, stripping bark from trees, robbing bird nests, and driving native reds from their dreys.
It is generally believed the grey s“invasion” succeeded because of their competitiveness and adaptability.
Different populations were thought to have interbred into a “supersquirrel” that led the charge.
The new study, comparing the DNA of nearly 1,500 grey squirrels in the UK and Italy, reveals different squirrel populations are still genetically distinct, meaning they have not interbred much.
In many cases, recently established populations of greys had relatives living far away. For instance, greys in Aberdeen were most closely related to those around the New Forest in Hampshire. Only humans could have helped them spread, say the scientists.
Lisa Signorile, who led the research, said: “Greys are not crazy invaders as we think – their spread is far more our own fault.”