British public urged to track black squirrels

Published: 30 January 2012 at 12:15

Study by Anglia Ruskin scientist aims to monitor spread of invading species

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It’s exactly 100 years since the first black squirrel was recorded in the UK and a scientist at Anglia Ruskin University is aiming to discover precisely how far they have spread since the first sighting in Woburn, Bedfordshire, in 1912.

The Black Squirrel Project is part of a study being undertaken by Helen McRobie, Lecturer in the Department of Life Sciences at Anglia Ruskin, to gather data on the geographical range of the black squirrel within the UK.

The British public are being encouraged to submit their squirrel sightings at the Black Squirrel Project’s website www.blacksquirrelproject.org to help map the population of this invading species.  It is believed the black squirrels living in the UK all came from a dozen that were released from a private collection in Bedfordshire.

Black squirrels, which originate from North America, are the same species as grey squirrels, and scientists at Anglia Ruskin have discovered that they have a piece of DNA missing on a gene that produces pigment, meaning they can only produce black fur.  So far this is the only known difference between black and grey squirrels.

The grey squirrel is also a native of North America but has become a well-established invader in the British Isles.  Between 1876 and 1929, over 100 grey squirrels were introduced to more than 30 different sites across England, Wales, Scotland and Ireland.  There are now more than two million grey squirrels in the British Isles, where they continue to spread and their numbers continue to rise.

Helen McRobie said:

“Black squirrel numbers seem to have risen steadily over the years and they have been spotted in Hertfordshire and Cambridgeshire, as well as Bedfordshire. 
“Although we know black squirrels are spreading, as yet we don’t have evidence that they are living elsewhere in the British Isles.  As it stands we know that the black squirrel gene has travelled approximately 50 miles in the last 100 years, which equates to half a mile a year.
“The aim of the Black Squirrel Project is to gather data on the geographical range of the grey and black squirrel in the British Isles, and the data may help explain why the grey squirrel has proved to be such a successful invader in the UK.  Therefore it would be great if as many people as possible can visit the website and submit their sightings.”