19/07/2024
LIFESTYLE To start this chapter we will dispel one myth about squirrels – neither red nor grey squirrels hibernate. Neither species goes into torpor as dormice, hedgehogs (Erinaceus europaeus) and bats do in the British Islands and Ireland. Red squirrels cannot go too long without venturing out to look for food, regardless of the weather, including snow. If the day is wet and windy, most squirrels will not venture as far as on a nice day but they are observed out in all weathers.
Natural food is cached in the autumn when seeds such as beech (Fagus sylvatica), hazel (Corylus avellana) and sweet chestnut (Castanea sativa) are abundant and retrieved later in the winter and spring. Fungi is also a favourite and plentiful in the autumn. This is the red squirrel’s version of a winter larder. Caches are generally buried but may be hidden in cracks high up in the trees as well. Smaller seeds, such as hawthorn (Crataegus monogyna), are also eaten and opened in the same way as hazelnuts, that is, split in half.
A squirrel’s nest is called a drey. Dreys are approximately 30cm in diameter and have no obvious entrance. They are usually built in mature trees at least 8m from the ground and generally against the trunk. The outside is made of twigs which will initially have leaves on. The inside is lined with dried grass, leaves or moss to make a soft, warm, dry home. When human habitation is nearby they may help themselves to something soft off the washing line or shred string and ball it up in their mouth to take back to their drey. Summer dreys may be little more than a platform of twigs and leaves and are not built to last. Winter dreys are very well made and can last for several years. There is no obvious difference between red and grey squirrel dreys. A tree hollow is the ultimate home and called a den. Squirrels build more than one drey or den nest at a time so that they may move home when the build-up of parasites, predominantly fleas, becomes unbearable.
It’s thought that squirrels use a map in their head coupled with a keen sense of smell to relocate their caches. They will also supplement their diet with other food such as lichen, fungi and mycelium found under bark. Predators may catch an unwary squirrel on the ground but in the trees they are relatively safe from most threats. Saying that, the rise in common buzzards (Buteo buteo) has taken a toll but some red squirrels, on the Isle of Wight at least, have adapted. There are now noticeably fewer dreys in the treetops. Some squirrels are building in more imaginative places and people have reported dreys built in lofts and barns. In 2019 a mother squirrel even had her kittens in a tractor roof!
Reds spend far more time in the trees than greys and prefer to feed from a vantage point such as a tree stump. Shoots, catkins, fungi, green cones and ripe cone seeds are available to them in a well- managed mixed woodland. A red squirrel’s slender build and light weight enables it to climb out to the very tips of the trees to take cones and nuts. When the seed crop is poor, fewer squirrels will survive the winter, the young and weak or older adults being most likely to succumb.
The beginning of the year heralds the start of the breeding season when females come into oestrus and the males’ te**es appear. Breeding details are in chapter 2. Squirrels notch the top of the nut using their incisors and split it in half. Depending on how abundant the autumn seed crop was, the squirrels should have enough stored nuts left from the autumn to Feeding stump. Note the split hazelnuts and chewed pine cone leavings.
A red squirrel will hold a home range, which it scent marks, but it does overlap with those of other squirrels. Males generally cover a wider range than females, especially once the breeding season starts. There is no definitive range size as much depends on the tree species within the wood, food production and the time of year. By the springtime, when the first litters of squirrels are leaving the nest, food is in short supply, making survival more challenging. If most of the stored caches have been used, shoots, buds and insects are foraged but do not have the nutritional value of nuts. Trees such as wych elm (Ulmus glabra) produce seeds in early summer and Scots pine cones are eaten in June, although they are still green. Wild cherry (Prunus avium) and Rowan (Sorbus aucuparia) can also provide food early in the summer. Statistics show that only around one in six red squirrels survive to see their first birthday. If they survive their first year, red squirrels can live up to around six years old in the wild. Food shortage, stress, disease and predation by birds and other mammals regulate the population. Personality also plays a part as subordinate animals will be bullied and therefore will stress, making them more vulnerable to illness.
