8 March 2019

Friend or Foe.... The Grey Squirrel


Furry, fast, occasionally chubby. Small, whiskered, bushy-tailed. An expert climber. A nut eater. And grey.
For those in the UK, everything was going great until the mention of Grey. You were probably thinking “cute” and “cuddly”, and feeling positive about this mystery mammal. Until you discover it is the grey and not the red squirrel.
Grey squirrels are a contradiction. They have all the characteristics of animals that people tend to love, and yet they are actively persecuted by humankind
So why such a bad press for grey squirrels?


Greys were deliberately introduced from North America in the late 19th century as an exotic addition to country estates. They soon spread across the UK, however, and today the invaders are the dominant squirrel across almost all of England and Wales and much of Scotland and Ireland.
But hostility towards invasive animals can’t explain the grey squirrel’s unpopularity – as other non-native species don’t get the same negative attention. The UK’s naturalised mammals include the brown hare, the edible dormouse, and sika deer. Even the much-loved rabbit is a Roman import.
Instead, grey squirrels are disliked because of the harm they cause to their native relatives, red squirrels. Studies have shown that greys can outcompete reds – the two species do not directly fight for resources, it is just that the greys are better at gathering the nuts and berries that both live off.
Grey squirrels are also unknowingly the carrier of a disease, squirrel pox, to which they are immune, but sadly the red is not. For red squirrels, the pox means painful scabs, ulcers and almost certain death (although some are finally developing resistance). The pox itself may actually be the chief “evil immigrant” in this eco-relationship, with the grey squirrel simply moving into vacant habitat following an epidemic among local red squirrels.



What to look for


As its name suggests, this squirrel typically has a grey coat with white undersides, though the coat colour can also be quite brown. It is up to 30cm long with a bushy tail almost as long as the body. The hind legs are bigger and more powerful than the front legs.


When and where to see


The grey squirrel can be found in a wide range of habitats, including deciduous, mixed deciduous/coniferous woodland, suburban parks and domestic gardens. It is active during the day, spending most of its time in the trees, but often coming down to the ground to search for food. It is a superb climber, moving rapidly through the trees and leaping between them with ease. It is one of the few mammals which can climb head first down a tree.
Grey squirrels do not hibernate, so may be seen at all times of the year. However, in winter they are far less active, sleeping for long periods, sometimes several days at a time, and they are less frequently spotted during this season.


Did you know?


  • Grey squirrels are mainly herbivorous, eating acorns, hazelnuts, berries, fungi, buds and shoots, and even bark. However, on rare occasions when plant food is very scarce they will eat insects, smaller rodents, bird eggs and nestlings.
  • Grey squirrels breed twice a year, December to February and May to June. The first litter of 2-6 pups is born in February to March, the second in June to July. The gestation period is about 44 days. The young are weaned at 7 weeks and leave the nest after 10 weeks.
  • Grey squirrels build a large, untidy looking nest (drey), in the treetops or hollow tree trunks. The drey is usually lined with moss, thistledown, dried grass, and feathers.
  • Squirrels collect nuts and seeds in the autumn and bury them in many scattered hiding places or caches around the wood. They have a highly-developed spatial memory and acute sense of smell, which aid them in finding the caches even weeks or months later. Even so, many caches remain uneaten each year allowing the seeds and nuts to grow, so helping to disperse the tree’s seeds through the woodland.


Facts Courtesy of Urban Wildlife and Napier University

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