Grey invaders get black looks in East Anglia

A young black squirrel, bottom left, plays with its grey siblings
A young black squirrel, bottom left, plays with its grey siblings
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BLACK may be the new grey for squirrels in the Thetford Forest area.

A new website launched by Anglia Ruskin University in Cambridge showing reported sightings of black squirrels reveals that Thetford Forest is a hotspot for them, while others have been sighted to the south of Bury St Edmunds.

Now, the scientist behind the survey, Helen McRobbie, a lecturer in biomedical science and molecular biology, is asking anyone involved in culling or pest control who kills a black squirrel to get in touch with her through the website

“I would really like a sample of DNA,” she said.

She has been studying the black squirrels, which are a genetic mutation of the grey squirrel known as melanism, for some time but wants the public to help in tracking their distribution.

American grey squirrels were introduced to about 30 sites in England between 1876 and 1929. By competing for food and spreading squirrel-pox, greys have taken over from the smaller native red squirrel, which is now only found in isolated pockets. Reds do better than greys in large conifer forests so may still be in Thetford Forest.

It is thought that about a dozen black squirrels escaped from the zoo at Woburn House, Bedfordshire, in the 1870s and there may now be as many as 25,000.

Ms McRobbie said: “We know they were introduced from Woburn and want to know how far they are spreading from there and how much faster they are spreading than the greys.”

They are still centred on Bedfordshire and East Anglia, but there have been sightings from elsewhere. The Ruskin map shows concentrations of them further east than maps previously published by the Forestry Commission.

Ms McRobbie added: “I want to keep tracking them over the years as they continue to spread. They might spread throughout the country, but that doesn’t mean they’ll take over.”

It is thought black was once the predominant strain in the USA but once Europeans began deforestation, the greys fared better. The Forestry Commission says it is unlikely the black mutation would have occurred naturally here.

Squirrel sightings can be reported at

n Report odd coloured birds – Page 104