I am an amateur naturalist trying to learn something about everything living in my garden.
To learn something about them I have been reading Squirrels by Jessica Holm (Whittet Books).
Together with the Red (Sciurus vulgaris) the Grey is one of two species of squirrel found in Britain. It is a North American import. The first pair was released by a Mr Broklehurst in the county of Cheshire in 1876. Famously, the Grey has thrived (indeed, they are legally classified as vermin), whilst the once common Red is today a protected species clinging on in a handful of isolated locations (I have only ever seen one myself- in Cumbria).
Why the populations have changed in this way is not entirely understood. It is often said (indeed, before reading Dr. Holt's book I too had lazily assumed) that the Greys have 'driven' the Reds from their 'territories'. This is false on two counts however: Firstly, in woodlands where both have been studied together its found that Reds and Greys do not show any undue aggression towards one another. Secondly (and a surprise to me) squirrels aren't territorial animals. The life of a squirrel is a 'roaming' one (though generally confined to some home range of a kilometer or so). Rather than all-out interspecies hostility, it seems that the Red population may have declined as a combination of diseases passed on by the invaders and because the smaller size of the Reds means they are less able to gather food in areas where the more avaricious Greys are eating much of it up. Totally, more study is necessary however.
A few additional things of interest I picked up from my reading are firstly that Reds and Greys normally carry distinct species of flea (Monopsyllus sciuronum for the Reds, Orchopeas howardii for the Grey). Mother Nature is nothing if not an expert in specialisation! Secondly, watching a squirrel work through a pile of nuts, it will sometimes be observed to discard one without opening it. These turn out to be bad nuts with withered kernels. How the squirrel determines this with the nut still in its shell is rather impressive. It weighs them in its paws. A neat party trick!
To end, the literature abounds with Squirrel poems and Beatrix Potter quotes, but for me there is only one winner of the prize for top squirrel literary moment:
The squirrels pulled Veruca to the ground and started carrying her across the floor.
"My goodness she is a bad nut after all" said Mr Wonka, "Her head must have sounded quite hollow" [...]
"Where are they taking her?" shrieked Mrs Salt.
"She's going where all the other bad nuts go" said Mr Willy Wonka. "Down the rubbish chute."
[Roald Dahl, Charlie and the Chocolate Factory]