THE GREY SQUIRREL
The talents of the grey squirrel, one of the most acrobatic of British mammals, are best displayed in its natural habitat -our broad-leaved woodlands. It is hardly surprising that the grey squirrel makes its home in wooded areas since its main source of food especially in autumn is the nuts, foliage and fruits that trees produce. Unfortunately the damage the squirrel can do to the bark of trees, which it gnaws for the sweet sappy tissue underneath, has led to its persecution by man. When driven from the woods, the grey squirrel will adapt to open country, as long as sufficient shelter is provided by hedges, bushes and individual trees.
Since its numerous introductions between 1877 and 1929 into the British Isles from North America, the grey squirrel has colonized most areas. However, in parts of north Norfolk, the Lake District, Northumberland and north Durham the red squirrel is the dominant species.
Outside its natural woodland habitat, the grey squirrel has been known to cross water, marshland and bogs – even to swim rivers. It has adapted well to different environments including urban areas. You will often find it in town parks and gardens, in fact wherever there are hedges, bushes or trees in which it can make a home.
The squirrel has become so familiar with these populated surroundings that it sometimes appears almost tame, and takes food from the hand if approached carefully. People living in towns are also well aware of the raids made on bird tables. In an effort to prevent this, some people hang nets of nuts from plastic clothes lines. This does not however deter the squirrel, which finds its way along the slippery line and, turning upside down like a blue tit, hangs by its hind feet to get at the nuts.
Even if you know where to look for grey squirrels, you may not always see them immediately since they have a marvellous ability to camouflage themselves. An obvious place to look for them is up in the tree-tops where they build their nest (drey). Even if the squirrels are too quick to catch sight of, you may see their tracks between the base of trees. About 3cm (l-1/2in) wide, these tracks show the four distinct claws of the forefeet and five of the hind feet; usually they are widely spaced with no signs of tail-dragging.
Another sign to look for is the stripped bark on the trunk oftrees. You may also find split shells or husks of nuts and fruit, cut tree shoots and buds, strips of bud scales or toothmarks on fungi. And listen for the characteristic scolding cry of ‘chuk-chuk-chuk’ which you may hear before you see the squirrel.
The grey squirrel’s summer coat is short, sleek and brownish-grey on the top of the body with a chestnut streak along the flanks and feet and often on the outer edges of the limbs. The tail hairs are thin with an indistinct white fringe. The winter coat is thicker and silver-grey on the top of the body. With yellowish-brown fur on the head and along the flanks; the legs and feet are grey, while the underneath of the body is white. The large, conspicuous bushy tail has dark grey fur with a white fringe. There is little difference in colouring between the males and females, but the young-before their first moult-usually have a greyer summer coat than the adults. In certain areas you will notice some distinct variations in colouring.
In south-east England you may even see white squirrels, particularly in Kent, Surrey and Sussex. These are albino greys and have reddish eyes – like all albinos. Some grey squirrels in this area have red-brown backs and can be confused with reds. In Bedfordshire, Cambridgeshire, Hertfordshire and Buckinghamshire you can find black (or melanic) squirrels. These are the descendants of about a dozen black squirrels introduced into the Woburn Estate in Bedfordshire shortly after the arrival of the first greys.
The grey squirrel gnaws at almost anything that grows on trees, including the tree itself-or more precisely the sappy tissue found under tree bark, especially of beech. It will occasionally take birds’ eggs and even young birds and insects. In other habitats it will also eat farm crops such as swedes, wheat, barley and oat shoots, and the grain from these cereals at the ‘milk’ stage, as well as when ripe.
All rodents have teeth which grow continually and must be worn down before they become dangerous and possibly pierce the palate. With the squirrel these are the incisors, which are trimmed by continual gnawing on nuts and seeds.
The squirrel gnaws its food on the spot or carries it to a safe eating place-either somewhere high in the trees or on a fence post or tree stump, where it can keep an eye on its surroundings. The squirrel’s eyes are large and set in the side of the head to give wide-angle vision. It also has an acute sense of smell, but its hearing is unexceptional. In the late summer and autumn the grey squirrel methodically sets about establishing caches to store its winter food. It will later remember the rough location of the cache and then smell out the exact position. Sometimes it forgets where the food is hidden and here you will often see stored nuts sprouting.
The squirrel is extraordinarily graceful and agile and can run up and down tree trunks, no matter how smooth the bark, with the greatest of ease. It will balance on the flimsiest twig and leap from branch to branch and tree to tree with complete confidence using its tail as a rudder.
On the ground the squirrel progresses in a series of short leaps or runs on an erratic course with its tail held out straight behind. It can reach speeds of up to 20 miles per hour. It pauses frequently to reconnoitre and sniffs the air, sitting upright on its hind feet with its tail flat along the ground and its ears erect. Surprisingly, the squirrel is an adept swimmer; it keeps its head and tail above the water, with the tail held up in its characteristic curve like a bushy sail.
Cycle of activity
The squirrel is active during the day, beginning before sunrise and ending well before sunset. It does not like extremes of temperature and in such cases will retreat to the cover of its drey. It cannot. However, spend more than two or three days without food and often comes out of the drey to forage even in adverse weather. Until recently it was mistakenly thought both grey and red squirrels hibernated during the winter or slept for long periods. Although you are unlikely to see squirrels in cold weather, they are about since their presence is given away, for example, by tracks in the snow.
Apart from games played by the young and the play which forms part of the courtship ritual, male squirrels spend a great deal of time in high-spirited chases through the tree tops, tail-biting and screaming. Whether this is play or aggression is not known. Apart from the ‘chuk-chuk-chuk’ call, listen also for a barking note, variations of purring noises and a vibrating sound (like the song of a grasshopper) made by males chasing females.
The grey squirrel has two mating seasons, the first occurring in May and the second in December. Courtship rituals involve display and chasing; a number of males sometimes pursue a female just before mating time, simultaneously engaging in running contests to see who gets the prize.
Preparing the drey
The squirrel’s nest (drey) is rounded (about the size of a football), close-knit and made of leaves, twigs, bark, grass and pliant stems of ivy. Found mostly in, it is often built away from the main trunk of the tree. Each drey is isolated and from a distance is easily mistaken for a crow’s nest, although the latter is an untidier affair.
After mating the female becomes the dominant of the sexes, driving out the male from the nest tree and constructing the drey in which she will give birth. As an alternative she may enlarge a previous one, or sometimes make her den in the hole of a tree trunk, possibly taking over a woodpecker’s old nest.
The female squirrel is a model mother and weans her blind and furless infants with great care, licking and cleaning each one individually. By the time the young squirrels are ten weeks old they are scrabbling about outside the drey and within another three weeks they are out on their own. They either wander away or are turned out by the mother, who must soon prepare for her next litter. Young female squirrels are capable of breeding six or seven months after birth and usually do so by the time they are a year old. Grey squirrels have been known to live as long as eight years. But this is an exceptional age. Most die in their first couple of years and only a very small number live beyond six years.
The grey squirrel avoids most of its predators by living in trees, but it is still vulnerable to owls, hawks, wild and domestic cats, dogs and occasionally stoats. Birds and squirrels co-exist quite happily for the most part, although occasionally birds will mob a squirrel.
The greatest enemy is undoubtedly man. Squirrels cause extensive damage to valuable hardwoods and, since the 1920s, strenuous efforts have been made to curb the population. Dreys have been destroyed and squirrels shot, trapped, poisoned and set upon by dogs. In 1937 the Government prohibited the importation and release or the keeping of grey squirrels in captivity-except under licence. All these measures were to no avail and the problem has yet to be solved.