The fauna of Scotland is generally typical of the northwest European part of the Palearctic realm, although several of the country's larger mammals were hunted to extinction in historic times and human activity has also led to various species of wildlife being introduced. Scotland's diverse temperate environments support 62 species of wild mammals, including a population of wildcats, important numbers of grey and harbour seals and the most northerly colony of bottlenose dolphins in the world.Matthews (1968) p. 254.
Many populations of moorland birds, including the black and red grouse, live here, and the country has internationally significant nesting grounds for seabirds such as the northern gannet.Fraser Darling and Boyd (1969) pp. 7, 98–102. The golden eagle has become a national icon,Benvie (1994) p. 12. and white-tailed eagles and ospreys have recently re-colonised the land. The Scottish crossbill is the only endemic vertebrate species in the UK.In the past, this claim has been made on behalf of other species such as the red grouse (now considered to be a sub-species of willow ptarmigan) and Irish stoat (Mustela erminea hibernica), also now considered to be a sub-species of stoat. Loxia scoticas position as a true species is a matter of debate but the current consensus is that it does have this status (see for example Miles and Jackman (1991) pp. 21–30 and Benvie (2004) p. 55.) The position of the freshwater fish the vendace Coregonus vandesius is disputed, with many authorities considering it to be a synonym of Coregonus albula.Adams, William Mark (2003) Future Nature. British Association of Nature Conservationists p. 30. Retrieved 14 July 2009. This source lists the UK's endemic species as being "14 lichens, 14 bryophytes, 1 fern, 21 higher plants, 16 invertebrates and 1 vertebrate (the Scottish crossbill)."Perhaps because endemic vertebrates are all but absent from the UK neither SNH nor JNCC appear to provide a definitive "list" but it is clear that the Scottish crossbill is the only endemic bird, (Gooders (1994) p. 273. and "Scottish Crossbill: Loxia Scotica" (pdf) JNCC. Retrieved 7 July 2009.) and that there are no endemic freshwater fish (Maitland, P. and Lyle A.A. (1996) "Threatened freshwater fishes of Great Britain" in Kirchofer, A. and Hefti, D. (1996) Conservation of Endangered Freshwater Fish in Europe. Basel. Birkhauser.) or mammals ("The British Mammals list" ppne.co.uk. Retrieved 7 July 2009.) in Britain. There are too few amphibians and reptiles native to the UK for there to be any doubt that no endemic species exist. The position is implied, although not stated by SNH in their Information and Advisory Note Number 49 "Priority species in Scotland: animals" Retrieved 7 July 2009. See also Myers, Norman (2003) "Conservation of Biodiversity: How are We Doing?" (pdf) The Environmentalist 23 pp. 9–15. Retrieved 7 July 2009. This publication confirms there is only one "endemic non-fish vertebrate species" in the British Isles, although it fails to identify the species concerned.
Scotland's seas are among the most biologically productive in the world; it is estimated that the total number of Scottish marine species exceeds 40,000. The Darwin Mounds are an important area of deep sea cold water coral reefs discovered in 1998. Inland, nearly 400 genetically distinct populations of Atlantic salmon live in Scottish rivers. Of the 42 species of fish found in the country's fresh waters, half have arrived by natural colonisation and half by human introduction.
Only six amphibians and four land reptiles are native to Scotland, but many species of invertebrates live there that are otherwise rare in the United Kingdom (UK).Miles and Jackman (1991) p. 48. An estimated 14,000 species of insect, including rare bees and butterflies protected by conservation action plans, inhabit Scotland. Conservation agencies in the UK are concerned that climate change, especially its potential effects on mountain plateaus and marine life, threaten much of the fauna of Scotland.See for example Johnston, I. (29 November 2006) "Sea change as plankton head north'". Edinburgh. The Scotsman. This report quotes James Lovelock's concern that global warming will "kill billions" of people over the coming century.
Habitats
Scotland enjoys diverse temperate environments, incorporating deciduous and coniferous woodlands, and moorland, montane, estuarine, freshwater, oceanic, and tundra landscapes. About 19% of Scotland is wooded, much of it in forestry plantations, but before humans cleared the land it supported much larger boreal Caledonian and broad-leaved forests.Although no one denies that past forests were much larger, they disagree about the timing and causes of the reduction. Many writers, from the 16th century author Hector Boece to the 20th century naturalist Frank Fraser Darling, believed that the woods were much more extensive in Roman times than today. However, it is now thought that deforestation of the Southern Uplands, caused by climate and by people, was well underway when the legions arrived. See Smout (2007) pp. 20–32. Although much reduced, significant remnants of the native Scots pine woodlands can be found. Heather moorland and peatland cover 17% of Scotland. Caithness and Sutherland have one of the world's largest and most intact areas of blanket bog, which supports a distinctive wildlife community. About 75% of Scotland's land is classed as agricultural (including some moorland) while urban areas account for around 3%. The coastline is long, and the number of islands with terrestrial vegetation is nearly 800, about 600 of them lying off the west coast. Scotland has more than 90% of the volume and 70% of the total surface area of fresh water in the United Kingdom. There are more than 30,000 freshwater lochs and 6,600 river systems.
Under the auspices of the European Union's Habitats Directive, 243 sites in Scotland are currently listed as Special Areas of Conservation (SACs), and 162 as Special Protection Areas (SPAs). Scotland's seas are among the most biologically productive in the world and contain 40,000 or more species. Twenty-four of the SACs are marine sites, and a further nine are coastal with marine and non-marine elements. These marine elements extend to an area of around . The Darwin Mounds, covering about , are being considered as the first offshore SAC. Quoting the Scottish Office. (1998). People and nature. A new approach to SSSI designations in Scotland. The Scottish Office, Edinburgh. Retrieved 2 January 2007."Offshore" in this context means not incorporating any land.
Mammals Scotland was entirely covered in ice during the Pleistocene glaciations.Save for the Atlantic outlier of St Kilda. Maclean (1972) p. 20. As the post-glacial weather warmed and the ice retreated, mammals migrated through the landscape. However, the opening of the English Channel (as sea levels rose) prevented further migrations, so mainland Britain has only two-thirds of the species that reached Scandinavia. The Hebridean islands off Scotland's west coast have only half those of Britain.Murray (1973) p. 72. Sixty-two species of mammal live wild in and around Scotland including 13 species found in coastal waters. The populations of a third of the land mammal species are thought to be in decline due to factors including environmental pollution, habitat fragmentation, changes in agricultural practices, particularly overgrazing, and competition from introduced species. No mammal species are unique to Scotland, although the St. Kilda field mouse, Apodemus sylvaticus hirtensis, is an endemic subspecies of the wood mouse that reaches twice the size of its mainland cousins,Benvie (2004) p. 645. and the Orkney vole or cuttick, Microtus arvalis orcadensis found only in the Orkney archipelago, is a sub-species of the common vole. It may have been introduced by early settlers about 4,000 years ago. There are various notable domesticated Scottish mammal breeds including Highland Cattle, the Shetland Pony, Eriskay Pony, Soay Sheep and Scottish Terrier.
Carnivores
The representation of the weasel family (Mustelidae) in Scotland is typical of Britain as a whole save that the polecat is absent and that Scotland is the UK's stronghold of the pine marten,Corbet and Ovenden (1984) pp. 180–86. although the purity of the latter breed is threatened by a release of American martens in northern England.Benvie (2004) p. 48. Scotland hosts the only populations of the Scottish wildcat (Felis silvestris silvestris) in the British Isles with numbers estimated at between 400 and 2,000 animals, and of the red fox subspecies Vulpes vulpes vulpes, a larger race than the more common V. v. crucigera and which has two distinct forms.Matthews (1968) pp. 231–32. The wildcat is at risk due to the inadequacy of protective legislation and is now considered at serious risk of extinction.Benvie (2004) p. 18.Hull (2007) pp. 184–89. In 2013 it was announced that the island of Càrna is to provide a sanctuary and breeding station in order to protect the species."Remote island plan to help save Scottish wildcats from extinction". (23 September 2013) Glasgow. The Herald. Retrieved 25 September 2013. Exterminations of the population of feral American mink, which were brought to Britain for fur farms in the 1950s, have been undertaken under the auspices of the Hebridean Mink Project and the Scottish Mink Initiative, which hopes to create a mink-free zone in a large area stretching from Wester Ross to Tayside.Haworth, Jenny (3 February 2009) "National cull may exterminate UK mink". Edinburgh. The Scotsman.Ross, John (12 May 2011) "Wildlife Groups agree £1m plan to wipe out American mink nuisance". Edinburgh. The Scotsman.
Other than occasional vagrants, among the seals only the Phocidae, or earless seals, are represented. Two species, the grey seal and harbour or common seal, are present around the coast of Scotland in internationally important numbers. In 2002 the Scottish grey seal population was estimated at 120,600 adult animals, which is around 36% of the world population and more than 90% of the UK's. The Scottish population of the common seal is 29,700, about 90% of the UK and 36% of the European total.
Rodents, insectivores and lagomorphs
Of the UK's red squirrels, 75% are found in Scotland. This species faces threats that include competition and disease from the introduced grey squirrel, and the 'Scottish Strategy for Red Squirrel Conservation' provides a framework for supporting its long-term conservation.The Scottish Wildlife Trust have announced a four-year project to commence in the spring of 2009 called "Saving Scotland's Red Squirrels". See "A new era for Scotland's red squirrels?" in Scottish Wildlife (November 2008) No. 66. Edinburgh. Research in 2007 credited the growing population of pine martens with assisting this programme by preying selectively on the grey squirrels.Watson, Jeremy (30 December 2007) "Tufty's saviour to the rescue". Scotland on Sunday. Edinburgh. It is theorised that because grey squirrels spend more time on the ground than the endangered reds, they are more apt to come in contact with this predator. Scotland has no population of the edible or hazel dormouse, or of the yellow-necked mouse, and the harvest mouse's range is limited to the southern part of the country. The St Kilda mouse and Orkney vole (see above) are endemic, but otherwise population distributions are similar to the rest of mainland Britain.Corbet and Ovenden (1984) pp. 152, 167–68. Colonies of black rats are thought to now remain only on the island of Inchcolm in the Firth of Forth, after a successful eradication programme on the Shiant Isles.