Clissold Park Redux #6: Invasion of the Edible Tree Rats
The cache, a small clik-lock box, is hidden at the north end of the park in a small patch of woodland where you are likely to see one of these creatures scampering around the trees or across the ground. It is also hidden close to the location of a previous cache of mine GC595PR Clissold Park Revisited #1: Lake Zone which was hidden on 19/7/14 and archived on 15/8/15 after some 59 finds and after the tree in which it was hidden had gone along with the cache. As no-one had placed another cache on the area some 3 years later, I thought I would try again . . .
The creature in question which some regard as cute, cuddly, and animated with their dark, oval eyes and twitchy, fluffy tail and others as a 'brutish, destructive, criminal' import and unwanted rodent invader . . . or 'tree rat!' - is the (eastern) gray squirrel (Sciurus carolinensis).
A prolific and adaptive species, it is native to eastern North America, where it is the most prodigious and ecologically essential natural forest regenerator (see here). In other parts of the world where it was introduced, it is regarded as an invasive species.
See here for comprehensive information on this controversial critter including this short documentary and here for a fact sheet. Listen here to their call and see one alarm calling here.
See here and here for more short videos and here for a video of young squirrels with their mother.
Grey Squirrel Issues and Responses
They were introduced to Britain in the 1870s, as fashionable additions to estates and spread rapidly across 
England, and then became established in both Wales and parts of southern Scotland.
In Britain and Ireland, it is not subject to natural predators, other than the European pine marten, which is generally absent from England and Wales. This has aided its rapid population growth - currently over 2.7 million and increasing rapidly (compared to only 120,000 and declining for the red squirrel). See Gallery for a startling graphic on this spread.
Although the grey squirrel is a pretty, appealing and entertaining little animal, it can be not only a great nuisance but a serious pest. The three greatest impacts of the grey squirrel to the UK environment, ecology and wildlife are to native red squirrels, trees, and many woodland birds.
On mainland Britain, they have largely displaced native red squirrels (S. vulgaris). Larger than red squirrels and able to store up to four times more fat, gray squirrels are better able to survive the UK winter. They have more young and can live at higher densities. They also carry the squirrelpox virus, to which red squirrels have little or no immunity*. When an infected gray squirrel introduces squirrelpox to a red squirrel population, its decline is 17-25 times greater than through competition alone.
*However, several cases of red squirrels surviving have been reported, as they have developed an immunity – although their population is still being massively affected. The red squirrel is also less tolerant of habitat destruction and fragmentation, which has led to its population decline, while the more adaptable eastern gray squirrel has taken advantage and expanded.
Foresters, gamekeepers, park keepers and many conservationists regard grey squirrels as serious pests, mainly because they damage trees. Young saplings (sometimes rare species) are destroyed and they gnaw off the bark of thin-barked hardwood trees, such as beech and sycamore, to get at the nutritious sapwood below. The raw scar left on the trunk encourages fungal attack and may lead to distorted growth.
It can be a serious nuisance in the garden especially to bird lovers. It is very bold and soon
learns to take 
food from bird tables and chew through baskets of peanuts. See Mission Impossible #1 and Mission Impossible #2 for amusing short videos on the extraordinary efforts it will take to reach the food despite numerous tricky obstacles, and here for a hilarious compilation of squirrels spinning wildly on a bird feeder.
It can also be a horticultural pest eating food crops.
There is growing evidence that grey squirrels adversely affect native woodland bird populations - in three ways. Firstly by eating eggs and baby birds from the open nests of birds such as thrushes and finches and discouraging birds from using nest boxes. Secondly, by using ideal nesting spots that would usually be occupied by birds such as the tawny owl, kestrel, jackdaw, stock dove and starling. In some areas it has been reported that squirrels can halt the breeding of tawny owls altogether by taking up these useful nesting sites. Thirdly, by eating the same food! Squirrels have been seen taking a bird's store of winter foods and their diet means that they are in direct competition with other birds such as the nuthatch, hawfinch and bullfinch.
In many forest areas, Forestry Commission and National Trust try to control the grey squirrel population by trapping and shooting. Gamekeepers shoot the squirrels on private estates.
In areas where relict populations of red squirrels survive, such as the islands of Anglesey and Brownsea, programs exist to eradicate gray squirrels in an effort to allow red squirrel populations to recover.
Ironically, 'fears' for the future of the gray squirrel arose in 2008, as the melanistic form began to spread through the southern British population.
The gray squirrel issue has featured in UK Parliamentary business numerous times over the years. A search for 'squirrel' on the web site yielded some 574 hits! For example in June this year in the Lords, during a Question for Short Debate regarding the critical decline of songbirds - seehere for the full, and interesting, debate,the devastating effect of invasive non-native species (like the gray squirrel and ring-necked parakeet) on local wildlife was lamented - 'they are over-abundant, over-sexed and over here!' remarked one peer.
In April, it was reported in a daily newspaper that wildcats could be reintroduced to England to help cull gray squirrels after a rich adviser to Environment Secretary Michael Gove offered to fund the initiative. Thousands of wildcats roamed Britain until they were hunted and killed from the 1700s onwards due to fears they would attack livestock.
In March, the Government revealed that it spent/will spend £100,000 of public money last year and this year on developing a contraceptive for grey squirrels to try to keep numbers down.
Proposals for (mass) culling in any form, however, have run into concerted opposition from (especially) 
environmental groups who argue that it is not only
unethical but that there is no good scientific evidence to show it is effective in achieving its aims. Human activities cause far greater damage to forests than those of gray squirrels. See for example Ode to the Demonised Grey Squirrel for the case for leaving the gray squirrel alone.
Under the UK Wildlife and Countryside Act 1981, it is illegal to keep, import and release grey squirrels without a special licence - instead it should be humanely destroyed.
And finally . . . squirrels were eaten a lot in the past and they are coming back on the menu!
Whether roasted, braised or fried, tandoori or Cajun-style, squirrels are becoming the delight of chefs and diners alike, who love them for their sweet taste. Squirrels have sold out at restaurants from Northumberland to Cornwall. The Wild Boar Hotel, near Windermere, has done squirrel in Asian-style pancakes, while squirrel, truffle, spinach and pinenut tortellini - with porcini veloute and parmesan wafer - is a winner at Stravaigin in Glasgow.
Celebrated chef Hugh Fearnley-Whittingstall has created several recipes for the animals. In spring, when squirrels mate and have litters and game suppliers proceed with a seasonal cull, the meat graces the menu at the London gastrodome St John in Smithfield, served with shallots.