Updated: Nov 17, 2019
The Red Squirrel has now become extinct in most of southern Britain. Two well known population outposts remain – those of Brownsea Island in Dorset and the Isle of Wight. It is no coincidence that these are island populations.
Since the introduction of the Grey Squirrel into the wild in 1876, the Red Squirrel has undergone a dramatic decline and, with the exception of the two colonies listed above, it is now largely restricted to remote colonies in northern England and Scotland. Without assistance, Grey Squirrels are unable to make sea crossings; consequently, islands upon which they have not been introduced retain their original populations of Red Squirrels.
Grey Squirrels outcompete Red Squirrels and also carry a disease – squirrel parapoxvirus (“squirrel pox”) – that is generally symptomless in the former but fatal for the latter. Grey Squirrels occupy territory more densely than reds – one hectare can support up to ten Grey Squirrels, whereas only one or two Red Squirrels can occupy the same amount of land. Grey Squirrels also eat more than Red Squirrels.
A potential difficulty faced by isolated populations of Red Squirrels such as those of Brownsea Island and the Isle of Wight is genetic weakness and the outbreak of diseases such as squirrel leprosy.
Finally I would like to thank the member of the security team at Osborne House who kindly allowed me to keep my pictures of Red Squirrels after I followed one onto land that was not open to the public.