Current population estimates of red squirrels stand at approximately 138,000 throughout the UK. Of that, it is estimated that approximately 120,000 are in Scotland, 3,000 in Wales and 15,000 in England. Red squirrels are mainly dispersed in England throughout the north with Kielder Forest, Northumberland supporting around 60% of the total population.
However, it is also thought that there could be as many as 2.5 million grey squirrels in the UK. As there is no current method of comprehensively surveying grey squirrels, this could be a considerable underestimation.
Red squirrels can be distinguished from grey squirrels in a number of ways. Surprisingly, fur colour is not definitive as both species can have wide variation in their coats. Coat colour can vary both geographically (i.e squirrels in different regions) and seasonally, as squirrels moult their body fur twice a year. The moult that occurs in the spring starts on the head and moves along the body, whereas the sequence in reversed in the autumn. Grey squirrels can often have very red fur and vice versa, as you can see in the photographs below.
One of the most obvious distinguishing factors is size. Red squirrels weigh between 270-360g and with a head and body length of 19-23cm. Grey squirrels are much larger, typically weighing between 400-720g with a head and body length of 25-30cm
Red squirrels are well known for having tufts on their ears. These tufts are present for most of the year but are moulted in late summer and regrow in early autumn. They are most prominent in the winter months. Grey squirrels never have ear tufts.
Another way to tell the difference between the species is to look at the tail. The hair on a grey squirrels tail is banded with different colours and the white tips on the tail create a ‘halo’ effect. Although red squirrels may have varying colour tails, like the white tail you can see below, the hair will all be one colour.