The red squirrel (Sciurus vulgaris), also called Eurasian red squirrel, is a species of tree squirrel in the genus Sciurus. It is an arboreal and primarily herbivorous rodent and common throughout Eurasia.

Taxonomy

thumb|Various red squirrel subspecies; A) S. v. vulgaris from Sweden, B) S. v. fuscoater from Germany, C) S. v. infuscatus from central Spain

thumb|, a dark-furred subspecies of red squirrel, in Vienna

There have been over 40 described subspecies of the red squirrel, but the taxonomic status of some of these is uncertain. A study published in 1971 recognises 16 subspecies and has served as a basis for subsequent taxonomic work. Although the validity of some subspecies is labelled with uncertainty because of the large variation in red squirrels even within a single region, At present, there are 23 recognized subspecies of the red squirrel. The Japanese squirrel, Sciurus lis, was also historically classified as a subspecies of S. vulgaris, although scientific opinion shifted towards classifying it as a distinct species beginning in the 1960s. The Japanese squirrel likely originated through peripatric speciation from a population of red squirrels that colonized the Japanese archipelago in the Pleistocene and speciated into a distinct population due to the isolation of the islands from the Eurasian mainland, emerging as a recognizable species by the Middle Pleistocene.

  • S. v. alpinus. Desmarest, 1822. (synonyms: S. v. baeticus, hoffmanni, infuscatus, italicus, numantius and segurae)
  • S. v. altaicus. Serebrennikov, 1928.
  • S. v. anadyrensis. Ognev, 1929.
  • S. v. arcticus. Trouessart, 1906. (synonym: S. v. jacutensis)
  • S. v. balcanicus. Heinrich, 1936. (synonyms: S. v. istrandjae and rhodopensis)
  • S. v. chiliensis. Sowerby III, 1921.
  • S. v. cinerea. Hermann, 1804.
  • S. v. dulkeiti. Ognev, 1929.
  • S. v. exalbidus. Pallas, 1778. (synonyms: S. v. argenteus and kalbinensis)
  • S. v. fedjushini. Ognev, 1935.
  • S. v. formosovi. Ognev, 1935.
  • S. v. fuscoater. Altum, 1876. (synonyms: S. v. brunnea, gotthardi, graeca, nigrescens, russus and rutilans)
  • S. v. fusconigricans. Dvigubsky, 1804
  • S. v. leucourus. Kerr, 1792.
  • S. v. lilaeus. Miller, 1907. (synonyms: S. v. ameliae and croaticus)
  • S. v. mantchuricus. Thomas, 1909. (synonyms: S. v. coreae and coreanus)
  • S. v. martensi. Matschie, 1901. (synonym: S. v. jenissejensis)
  • S. v. ognevi. Migulin, 1928. (synonyms: S. v. bashkiricus, golzmajeri and uralensis)
  • S. v. orientis. Thomas, 1906. Ezo Red Squirrel (Hokkaidō).
  • S. v. rupestris. Thomas, 1907
  • S. v. ukrainicus. Migulin, 1928. (synonym: S. v. kessleri)
  • S. v. varius. Gmelin, 1789.
  • S. v. vulgaris. Linnaeus, 1758. (synonyms: S. v. albonotatus, albus, carpathicus, europaeus, niger, rufus and typicus)

Description

thumb|A red squirrel eating hazelnuts

thumb|Underparts are generally white-cream-coloured

thumb|Skull of a red squirrel

The red squirrel has a typical head-and-body length of , a tail length of , and a mass of . Males and females are the same size. It is also used to signal during social interactions. Melanism is common, particularly in continental, boreal, and montane populations,

In Great Britain, Ireland and in Italy, red squirrel populations have decreased in recent years. This decline is associated with the introduction by humans of the eastern grey squirrel (Sciurus carolinensis) from North America. However, the population in Scotland is stabilising due to conservation efforts.

Ecology and behaviour

The red squirrel is diurnal; activity typically begins at sunrise, but continues after sunset.

Red squirrels do not hibernate. During the winter, however, they may remain within their nest for several days during severe weather. alongside acorns and nuts. Other food sources include fruits and berries, fungi, lichens, young plant shoots, vegetables, garden flowers, and tree sap.

More rarely, red squirrels may also eat invertebrates, bird eggs, or nestlings.

Excess food is put into caches called "middens", either buried or in nooks or holes in trees, and eaten when food is scarce. Caching occurs most frequently during the fall to create food stores for the winter. This scatter-hoarding behavior is more commonly observed in deciduous forests than in coniferous ones. Caching is done most frequently with hard, low-perishability foods such as nuts, acorns, and conifer cones, but fungi are sometimes also stored in trees. Scent markings are left on trees by rubbing with facial glands, usually at habitual sites. Urine is also used for this purpose. Gestation is about 38 to 39 days. The young are looked after by the mother alone and are born helpless, blind, and deaf. They weigh between 10 and 15g. Hair begins to emerge at 8-9 days of age and covers the body at 21 days.

Predators

Red squirrels are preyed upon by a number of predators, including the pine marten, the European wildcat, and predatory birds such as owls, the Eurasian goshawk, and the common buzzard. Stoats also take nestlings. The red fox and domestic cats and dogs also prey on red squirrels when these are on the ground. Domestic cats in particular are a primary predator in suburban areas. However, the eastern grey squirrel appears to be able to decrease the red squirrel population for several reasons:

  • The eastern grey squirrel carries a disease, the squirrel parapoxvirus, that does not appear to affect their own health but will often kill the red squirrel. It was revealed in 2008 that the numbers of red squirrels at Formby (England) had declined by 80% as a result of this disease, though the population is now recovering.
  • The eastern grey squirrel can better digest acorns, while the red squirrel cannot access the proteins and fats in acorns as easily.
  • The eastern grey squirrel inhabits broadleaf forests at higher densities than red squirrels, and pilfers red squirrel food caches.
  • Pressure from grey squirrels also appears to decrease effective reproduction among red squirrels. Outside the UK and Ireland, the impact of competition from the eastern grey squirrel has been observed in Piedmont, Italy, where two pairs escaped from captivity in 1948. A significant drop in red squirrel populations in the area has been observed since 1970, and it is feared that the eastern grey squirrel may expand into the rest of Europe.

Conservation

The red squirrel is protected in most of Europe, as it is listed in Appendix III of the Bern Convention; it is listed as being of least concern on the IUCN Red List. However, in some areas it is abundant and is hunted for its fur. supports red squirrel conservation on the island, and islanders are actively recommended to report any invasive greys. The population decrease in Britain is often ascribed to the introduction of the eastern grey squirrel from North America.

In addition to competition with the grey squirrel, the red squirrel is also sensitive to habitat fragmentation, and loss of suitable habitat is a significant threat to red squirrels over large portions of their range.

Projects

thumb|250px|Protecting the red squirrel in [[Clocaenog Forest, Wales]]

thumb|Red squirrel at a feeding tray in the [[Lake District, England.]]

In January 1998, eradication of the non-native North American grey squirrel began on the North Wales island of Anglesey. This facilitated the natural recovery of the small remnant red squirrel population. It was followed by the successful reintroduction of the red squirrel into the pine stands of Newborough Forest. Subsequent reintroductions into broadleaved woodland followed and today the island has the single largest red squirrel population in Wales. Brownsea Island in Poole Harbour is also populated exclusively by red rather than grey squirrels (approximately 200 individuals).

Mainland initiatives in southern Scotland and the north of England also rely upon grey squirrel control as the cornerstone of red squirrel conservation strategy. A local programme known as the "North East Scotland Biodiversity Partnership", an element of the national Biodiversity Action Plan was established in 1996. This programme is administered by the Grampian Squirrel Society, with an aim of protecting the red squirrel; the programme centres on the Banchory and Cults areas. In 2008, the Scottish Wildlife Trust announced a four-year project which commenced in the spring of 2009 called "Saving Scotland's Red Squirrels".

Other notable projects include red squirrel projects in the Greenfield Forest, including the buffer zones of Mallerstang, Garsdale and Widdale; the Northumberland Kielder Forest Project; and within the National Trust reserve in Formby. These projects were originally part of the Save Our Squirrels campaign that aimed to protect red squirrels in the north of England, but now form part of a five-year Government-led partnership conservation project called "Red Squirrels Northern England" to undertake grey squirrel control in areas important for red squirrels. However, grey squirrels were found to outnumber red squirrels in both Cumbria and Northumberland for the first time. In Northumberland grey sightings were 25% higher than reds, and in Cumbria they were 17.3% higher.

On the Isle of Wight, local volunteers are encouraged to record data on the existing red squirrel population, and to monitor it for the presence of invasive greys; as the red squirrel is still dominant on the island, these volunteers are also requested to cull any greys they find. In order to protect existing populations, increasing amounts of legislation have been issued to prevent the further release and expansion of grey squirrel populations. Under the Wildlife and Countryside Act 1981, it is an offense to release captured grey squirrels, indicating that any captured individuals must be culled. Additional rules covered under the WCA's Schedules 5 and 6 include limitations on the keeping of red squirrels in captivity, and also prohibits the culling of red squirrels.

Research undertaken in 2007 in the UK credits the pine marten with reducing the population of the invasive eastern grey squirrel. Where the range of the expanding pine marten population meets that of the eastern grey squirrel, the population of these squirrels retreats. It is theorised that, because the grey squirrel spends more time on the ground than the red, they are far more likely to come in contact with this predator.

During October 2012, four male and one female red squirrel, on permanent loan from the British Wildlife Centre, were transported to Tresco in the Isles of Scilly by helicopter, and released into Abbey Wood, near the Tresco Abbey Gardens. Only two survived and a further 20 were transported and released in October 2013. Although the red squirrel is not indigenous to the Isles of Scilly, those who supported this work intend to use Tresco as a "safe haven" for the endangered mammal, as the islands are free of predators such as red foxes, and of the Squirrel parapoxvirus-carrying grey squirrel.

The UK Animal and Plant Health Agency (APHA) has proposed a method of non-lethal control of grey squirrels as part of a 5-year Red Squirrel Recovery Network (RSRN) project. The planned method for control would be by administering oral contraceptives via a grey squirrel-specific feeder, which would selectively allow feeding based on body weight in order to avoid inadvertently distributing the contraceptive to red squirrels as well. This project has received National Lottery Heritage funding.

Cultural significance

thumb|Red squirrels on a [[German heraldry|German coat of arms]]

thumb|Russian squirrel bellies being prepared in China for use as [[fur clothing, showing the distinctive pattern that developed into the vair tincture in heraldry]]

thumb|[[Coat of arms of Jane Seymour, one division vair from her relationship to the Beauchamps]]

thumb|"Squirrel" illustration from British Mammals by A. Thorburn, 1920

The red squirrel is the national mammal of Denmark.

Red squirrels have historically been hunted both as a game animal and for their furs.

Red squirrels are frequently valued as appealing wildlife in urban settings. However, they are also seen as a pest in orchards and gardens due to their habit of peeling off tree bark to feed on cambium.

References

  • ARKive: photographs and videos
  • A partnership to save the red squirrel, between the Scottish Wildlife Trust, et al.
  • WildlifeOnline: Natural History of Tree Squirrels
  • Red squirrels make a comeback as culling of grey rivals brings results
  • Acute Fatal Toxoplasmosis in Three Eurasian Red Squirrels