My garden in London backs on to a park which is maintained as a wildlife sanctuary, and much of the wildlife finds its way across the back fence into the garden - especially when it knows that there's food on offer. One of the most frequent visitors is a little grey squirrel.
Grey squirrels aren't native to Britain. They were first introduced in 1876, from America. But they bred rapidly and soon took over from the native red squirrels, once widespread. There are now estimated to be about 2.5 million greys as opposed to only 120,00 - 160,000 reds, which are mostly found in the coniferous forests of Scotland.
Why has the red squirrel declined so dramatically in numbers? Destruction of the woodlands which are the red squirrel's natural habitat is one reason. The grey squirrel has a number of advantages when competing for food. It can eat acorns, which the red squirrel can't, and which are often now the main food source in the parks and woodlands where the greys are found (I just wish they'd remember where they bury them - you can't imagine how many sapling oaks I pull out of my garden each time I'm here.) In addition, where hazel nuts (a principal food source for the reds) are growing, the greys have the advantage of being able to eat them when they are still unripe - which the reds can't. The greys therefore get there first, leaving fewer for the reds.
But one of the main reasons for the drop in numbers seems to have been a virus called the parapox virus. The greys are unaffected by it, but evidence suggests that they can and do carry and spread it. And for the reds, it's deadly.
It's estimated that red squirrels will disappear from and area within 15 years of the introduction of the greys and they are now a protected species, with projects to reintroduce them to their natural habitats being carried out in various places. One highly successful case was in Anglesey in North Wales, where culling the greys resulted in the re-establishment of a thriving population of reds.
The greys, on the other hand, are seen as vermin and can be legally killed. Local DIY shops and gardening centres here are full of squirrel traps. You do need the permission of the landowner to set them however, so if any of my future tenants are reading this - you don't have it. If there is any control to be done, I feel it should be done in a planned way by the authorities, not by individuals. And in fact research is apparently being done to find an oral contraceptive which can be left where the greys will eat it but not other animals. Squirrels on the pill - the mind boggles. But a far more acceptable solution to my mind than people taking the problem into their own hands.
I like the squirrels though and wouldn't want to lose them from my garden. Yes, they can be a nuisance. They raid the bird feeders and the fruit trees, dig holes in the garden to bury their nuts and acorns, and dig up and eat the flower bulbs. (Yikes, I bought 200 daffodil bulbs to plant in the garden the other day - that should keep ours going for a couple of weeks.) And more seriously, they will eat birds eggs and baby birds. But they're fun to watch and brighten up the garden considerably. And they provide interest for our neighbours' cat, who is convinced that one of these days he'll be quick enough to catch one. Not a hope in hell. They just leap across the garden, whizz up a tree and sit at laugh at him. I swear I saw one throwing a nut down at him the other day ...
National Geographic News
UK Biodiversity Action Plan
London Evening Standard
The Friends of the Anglesey Red Squirrels