Our red squirrel (Sciurus vulgaris) is native to Britain, but its future is increasingly threatened by an US invader — the grey squirrel (Sciurus carolinensis).

At this time of year the US greys are mostly tucked up in their dreys while the hardy red natives do not hibernate but store fungi in trees to eat over the winter months.

Both species will have put on weight in the autumn, when food was plentiful, to help them through the winter.

This is important for breeding females, so that they are in good condition for producing young.

There are estimated to be only 140,000 red squirrels left in Britain, with over 2.5 million greys spreading across the mainland.

Red squirrels range widely, especially when looking for mates. They produce young, called kittens, in the spring and can reproduce a second time in the summer if conditions are right.

You might see their courtship displays in the trees on woodland walks.

Females usually have two or three kittens, but litters can be of up to half a dozen young.

Young red squirrels are weaned off their mother’s milk after about 8-12 weeks, when they have developed a complete set of teeth.

Red squirrels are seed eaters. They favour pine cones but also eat larch and spruce but their diet also includes fungi, shoots and fruits of shrubs and trees and sometimes birds’ eggs.

The main threats to the survival of the reds are the increasing number of grey squirrels and the fact that they carry a disease called squirrel pox virus which is far more harmful to reds than to greys.

Many squirrels of both species also die in road traffic accidents. Gardeners angered by raids on bird feeders also kill large numbers.

The greys can feed more efficiently in broad-leaved woodlands and can survive at higher population densities than red squirrels.

The main predators of red squirrels are birds of prey such as goshawks and the rare pine marten. In some urban areas, domestic cats are also a threat when squirrels go into gardens to feed.

The reds usually have russet red fur, although coat colour can vary with some reds appearing very grey — just to further confuse some grey squirrels can have red fur down their backs and on their feet.

Varieties of the grey squirrel can be black, albino or brunette.

Red squirrels are smaller and have ear tufts — large tufts in winter — while grey squirrels are stockier and rounder.
It is hard to tell between sexes as there is little difference between males and females.

Reds are very elusive and spend much of their time high in trees.

Clues to look for include large dreys in trees, scratch marks on bark and chewed pine cones that look like chewed apple cores.

Grey squirrels — originally from North America — were released in Britain by irresponsible 19th-century aristocrats and landowners.

They are active during the day, foraging for food in trees and on the ground and often visit peanut feeders in gardens. In the autumn they spend time storing nuts to eat during the winter.

Their breeding cycle falls in between January and April and, if food is plentiful, they may have a second litter in the summer.

The grey lives on a diet of acorns, bulbs, tree shoots, buds, fungi, nuts and roots — occasionally, it will take birds’ eggs and chicks. It has a great fondness for robbing garden peanut feeders.

Their expansionism threatens not the survival of native red throughout Britain but also leads to the destruction of our ancient woodlands.

In an attempt to control numbers many are being shot and increasingly the meat is being sold by game dealers and country butchers. It is even being made into pasties and pies — it tastes rather like duck.

Some good places to see red squirrels: Kielder Forest, Northumberland; Formby, Merseyside; Cannock Chase, Staffordshire; Isle of Wight; Brownsea Island, Dorset; Hiraethog Forest, Denbighshire; Plas Newydd, Anglesey. In both Northern Ireland and Scotland red squirrels are far easier to find.