The fauna of the Faroe Islands is characterized by the remote location of the islands in the North Atlantic Ocean. There are few terrestrial species, but an abundance of breeding seabirds and marine animals. Some subspecies and breeds are endemic. All land mammals were introduced by humans.
Birds
The avian fauna of the Faroes is dominated by seabirds and birds attracted to open land like heather, probably due to the lack of woodland and other suited habitats. There are species of eider, starling, wren, guillemot, and black guillemot which are endemic to the islands. Puffins (Fratercula arctica), razorbills (Alca torda), and guillemots (Uria aalge), are very common seabirds in Faroe. Gannets (Sula sula) are common around the islands, but only breed on Mykines. Black guillemots (Cepphus grylle), eiders (Somateria mollissima) and shag (Phalacrocorax aristotelis) are common around the coast and the fulmars (Fulmarus glacialis) which immigrated to the islands in the 19th century have a steadily growing population. There are six species of seagulls (Larus) and the storm petrel (Hydrobates pelagicus) colony on Nólsoy is the largest in the world.
Inland birds are fewer in numbers. Oystercatcher (Haematopus ostralegus) (the national bird), whimbrel (Numenius phaeopus), common snipe (Gallinago gallinago) and Arctic tern (Sterna paradisea) are common on the heather hills. The Faroese starling (Sturnus vulgaris ssp. faroeensis) is the biggest starling in the world, and is very common in and around human habitation together with house sparrow (Passer domesticus). The islands' population of blackbirds (Turdus merula) has been steadily growing since it was established in the 1940s. Hooded crows (Corvus cornix) and the North Atlantic subspecies of raven (Corvus corax varius) are also common around areas of human habitation. Until the 19th century, a uniquely coloured variant of raven - the pied raven - occurred in the islands. This was a colour morph of the North Atlantic raven, rather than a subspecies in its own right. This colour variation was unique to the Faroe Islands, and created a high demand for the birds among foreign collectors. This may have helped wipe out the raven's unique colour morph within the Faroese population; the last confirmed record of a pied raven was in 1902.
Land mammals
The land mammals of Faroe have all been introduced, accidentally or deliberately, by people. Although nine species of wild land mammal have been reported on the Faroe Islands, only three have survived and are thriving on the islands today: mountain hare (Lepus timidus), brown rat (Rattus norvegicus) and the house mouse (Mus domesticus).
Mountain hares were introduced from Kragerø in Norway in 1854. The first years, some of the hares developed a white coat in winter, like their ancestors from Norway, but after a few decades, due to the oceanic climate with its lack of snow cover, the Faroese hares had adopted common traits with the Irish hares (Lepus timidus hibernicus) staying brown most of the year and turning grey in winter. Hares are present on all but three of the smaller islands, Koltur, Stóra Dímun and Lítla Dímun.
The Faroese house mouse was probably introduced accidentally from Britain by the Irish monks as early as the 6th century. It is the Western European house mouse (Mus domesticus) but has earlier been labelled as Mus musculus. This naming has also been used to name the subspecies which has evolved in the isolated island populations. The Nólsoy house mouse is a subspecies called (Mus musculus faroeensis) and the Mykines house mouse is also a subspecies called (Mus musculus mykinessiensis). However, a recent study, based on DNA-analyses, has shown that mice on the most remote islands (Hesti, Fugloy, Mykines and Nólsoy) are characterized as M. m. domesticus, whereas the mice on the better connected islands (Sandoy and in Torshavn) are mixed and have both M. m. musculus and M. m. domesticus genetic elements. Furthermore, the investigation indicated that the majority of the mice have their origins in south-western Norway, in agreement with human historical data, while the mice on the island of Sandoy may have arrived from the British Isles or from Denmark. The M. m. musculus genetic component appears to derive from recent immigrant mice from Denmark. The wood mouse or field mouse (Apodemus sylvaticus) was recorded on the Faroe Islands in the 17th century, but has not been recorded since. These recordings might have been mistaken. The house mouse is present on the islands Mykines, Streymoy, Fugloy, Hestur, Nólsoy and Sandoy. From time to time they have been located on Eysturoy, but they have never managed to establish themselves there due to the presence of the brown rat.