Red Squirrel

Two different animals share the name red squirrel. This page is about the Eurasian red squirrel, Sciurus vulgaris, also called the European red squirrel, the native squirrel of the forests of Europe and northern Asia. The American red squirrel, Tamiasciurus hudsonicus, lives in the conifer forests of Canada, Alaska, the northern United States and the Rocky Mountains, and belongs to a different genus. It is smaller, at around 200 to 250 grams, and has a white ring around each eye, a dark stripe along its side in summer and much shorter ear tufts. In North America it is also called the pine squirrel or chickaree. It is famous for its loud, rattling chatter and for defending a territory around a midden, a heap of cone scales that can grow over the years to several meters across. The Eurasian red squirrel is quieter, less territorial and hides its food in many small caches spread through the forest.

The red squirrel is small and light: its body measures 19 to 23 centimeters, the bushy tail adds another 15 to 20, and an adult weighs only 250 to 340 grams, about half as much as a gray squirrel. Its most famous features are the long tufts of hair on the tips of the ears. They grow in autumn and are at their fullest in winter, then thin out or disappear during the summer molt, so a red squirrel in July can look surprisingly plain. The tail is replaced only once a year and can bleach to a pale cream by late summer in some animals. Despite the name, the color varies a lot: from bright orange red in Britain and western Europe to brown, gray brown or almost black in parts of the Alps, Scandinavia, Siberia, Korea and Japan. Dark and red squirrels can even appear in the same litter. The belly is always white or cream, which is a quick way to tell a dark red squirrel from other species.

The red squirrel has one of the widest ranges of any tree squirrel, covering coniferous, broadleaf and mixed forests from Ireland, Britain and Portugal across Europe and Russia to Mongolia, northern China, Korea and the Japanese island of Hokkaido. It thrives especially in mature pine, spruce and larch woodland, where cone crops are reliable and the canopy offers cover from predators, but it also lives in beech and oak forests, parks and large gardens. Densities are highest in the forests of Scandinavia, Finland and Russia. In Portugal it disappeared around the end of the sixteenth century and has returned in recent decades, spreading in from Spain. In the Caucasus and parts of Central Asia, including Georgia, Armenia, Azerbaijan and the Tian Shan, squirrels from Siberia were released during the twentieth century and are now established. In Britain, Ireland and northern Italy, the spread of the introduced gray squirrel has pushed red squirrels out of much of their former range.

Food choices shift with the seasons, but seeds from conifers form the backbone of the red squirrel's diet throughout much of the year. It extracts seeds from pine, spruce, and larch cones with remarkable precision, stripping scales cleanly to reach the kernel inside. Hazelnuts, acorns, beech mast, berries, tree bark, and the fruiting bodies of fungi all supplement its intake depending on what is available. In autumn, red squirrels cache large quantities of food by burying it in shallow scrapes across the forest floor. They relocate many of these stores by memory and smell, but forgotten caches can germinate and grow into new trees, making the squirrel an unintentional contributor to forest renewal. Young shoots and bird eggs are also taken on occasion.

Red squirrels can mate from late winter onward, and the chases of males following a female through the treetops are a common sight from January to March. After a pregnancy of about 36 to 42 days, the female gives birth in her drey to a litter of usually three or four young, called kits or kittens, and occasionally as many as seven. In years with a good cone or nut crop, many females raise two litters, the first born around March to April and the second in early to mid summer; in poor years they may not breed at all. Newborn kits weigh only 10 to 15 grams and are blind, deaf and hairless. Their eyes open at about four weeks, they start leaving the nest at around seven weeks, and the mother nurses them for 50 to 70 days. The male takes no part in raising them. By about three months the young are independent and disperse to find their own home range, which is when many fall to predators or traffic.

For the most part, red squirrels lead solitary lives, coming together only to mate or when food sources briefly concentrate them in the same area. They are active during daylight hours, with peaks of foraging in the early morning and again before dusk. Each individual constructs one or more dreys, spherical nests built from interwoven twigs and lined with soft moss, grass, and bark strips, typically wedged into a fork high in a tree. These serve as sleeping quarters and, for females, as nurseries for raising young. Red squirrels do not hibernate, but in severe winter cold they may remain in the drey for several days at a time, drawing on cached food reserves. Their agility in the canopy is exceptional, allowing them to leap distances of up to two meters between branches.

The red squirrel is not endangered worldwide, but in Britain it is listed as Endangered on the Mammal Society's Red List, and the reason is the gray squirrel. Gray squirrels were brought from North America to Britain from the 1870s, and they spread across England and Wales during the twentieth century. They are about twice as heavy, live at higher densities and can digest acorns, which red squirrels cannot use well, so in broadleaf woodland they simply outcompete them for food. Worse, gray squirrels carry squirrelpox, a virus that does them little harm but kills red squirrels within about two weeks. Where both meet, reds usually vanish within a few years. A 2018 review estimated about 287,000 red squirrels in Britain, most of them in Scotland, against only about 38,900 in England, where gray squirrels number around 1.94 million. Ireland, where grays arrived in 1911, and northern Italy, where they were released near Turin in 1948, show the same pattern. One surprise ally is the pine marten: where martens have recovered in Ireland and Scotland, gray squirrels decline and reds come back.

Globally there are many millions, and the IUCN lists the red squirrel as Least Concern because of its huge range and large populations in Scandinavia, Russia and Asia, where gray squirrels have never arrived. Across most of continental Europe it remains common, and in Germany, Poland, Scandinavia or the Alps it is a familiar sight in city parks. The worries are local, above all in Britain, and in England they survive mainly in Northumberland, Cumbria, Merseyside's Formby and islands free of gray squirrels such as the Isle of Wight and Brownsea. Some conservation work has paid off: on the Welsh island of Anglesey, the removal of gray squirrels let red squirrels recover from a few dozen in the late 1990s to several hundred. In Italy, European funded projects have tried to stop the gray squirrel spreading from Piedmont and Lombardy toward the Alps, France and Switzerland, which would put continental red squirrels in the same position as British ones. In the United Kingdom the species is protected by law, and planting conifer woods that favor reds over grays is another tool.