Introduced from N.USA in 1870s. They are widely distributed across the UK and there are estimated to be 2.5 million in the country . Our native squirrel , the Red , is not able to compete with the bigger and stronger Grey and there are about 10-15000 Reds left . The Grey squirrel carries squirrel pox that the Red has no immunity to . Also our American import can also store up to 4 times more fat than the Red and stands far more chance of surviving a hard winter . The Grey prefers broad-leafed trees for nesting and feeding and the Red favours coniferous forests .
Squirrels bury food for later use , this is known as caching. They are very good at remembering where the food is and they do this by remembering distant and nearby landmarks. They also use deceptive behaviour . If they think that are being watched they will go through the motions of digging a hole , burying the food , putting the food in the hole , covering it up , but all the time the food is in their mouth !
The Grey squirrel can also climb headfirst down a tree trunk . It can turn its feet so that the claws on its hind paws are pointing backwards and can grip the tree bark . They build a sort of nest called a drey . They are in the forks of trees made mostly from dried leaves and twigs and roughly spherical in shape and lined with moss , feathers , grass and sometimes bits of material or even plastic bags ! In very cold winters they may share the drey with others . They may also use holes in trees , building or even lofts in houses if they can gain access . They are brilliant survivors and have adapted to living closely to humans superbly well .
They are mostly active during the early and late hours of the day , called crepuscular . Squirrels don’t hibernate . Their breeding seasons are Dec-feb and May-June . Average litter is 1-4 babies gestation period is around 44 days. The young are weaned at about 10 weeks . Only 1 in 4 will make it to 1year old . They are usually 1 year old before breeding (females) and 1-2 years(male). In captivity they have lived up to 20 years but in the wild an average of 6 yrs is more usual .
They eat tree bark , buds , berries , hazelnuts , walnuts , acorns ,seeds . They are superb raiders of bird tables and will help themselves to fat balls , suet pellets , coconut and most things it finds there .
Grey squirrels split people into the love them or hate them zone . Yes they can be pests and the Red is a beautiful little creature but the Grey was physically brought here by humans . It didn’t choose to come it was forced to and all it has done is learn to survive . They are great opportunists, amazing acrobats and intelligent mammals .