Fauna of the Isles of Scilly

The Isles of Scilly are an archipelago off Land's End, Cornwall. Little of the fauna on, above or in the seas surrounding the isles was described prior to the 19th century, when birds and fish started to be described. Most records of other animals date from the 20th century onwards.
Historical overview.
There are few pre-19th-century records for animals. William Borlase published "The Natural History of Cornwall" in 1758, commenting on the number of rabbits, and Jonathan Couch's "A Cornish Fauna" gave an account of some the animals known in Cornwall and the Isles of Scilly. In the 19th century, following the fashion of the time, birds were shot and stuffed, especially by Augustus Smith and his predecessors on Tresco. Egg collecting was allowed and in the Natural History Museum there are, in the collection, forty-five eggs taken between 1880 and 1936 from Annett, even though it was a bird sanctuary. Newspapers recorded some of the fish caught but there was little recording of other groups of animals.
It was in the 20th century when regular accounts can be found for other animal groups following visits from naturalists who often published their observations in the scientific literature. For example, William Bristow visited the islands on three occasions from 1927–1934, recording spiders including on some of the uninhabited islands. The Cornwall Bird Watching and Preservation Society published bird reports from the 1930s onwards and the Isles of Scilly Bird Group (founded 2000) took over publishing their own annual reports – "Isles of Scilly Bird and Natural History Review" – which included other groups of animals such as the diptera.
Planarian (flatworms).
Fourteen species of terrestrial flatworms have been recorded in Britain and Ireland with five found on the Isles of Scilly. Only three or four of the fourteen species are native with two recorded on Tresco.
Odonata.
"The Atlas of the Dragonflies of Britain and Ireland" published in 1996 listed just three species; blue-tailed damselfly, common darter (both breeding residents) and the migrant hawker. The pools can be slightly brackish at times and only species that can tolerate these conditions can establish populations on the islands.
Steve Jones compiled a list which was published in the "Cornwall Dragonfly Group Newsletter" (numbers 6–8) and the list below is based on that information. In comparison, at that time, Cornwall had 23 breeding species and 28 species recorded.
Orthopteroid.
The Orthopteroids have been recorded in Scilly since 1890 and specialists have visited the islands since 1989 to give, what is considered, complete coverage of these insects. The list below is taken from "Orthopteroid Insects on Scilly" (2001) with additional records referenced.
Lepidoptera.
In 1992 Michael Hicks and John Hale began to regularly record the moths on St Agnes using a mercury vapour moth trap, initially in the central part of the island and later also on the coast and Gugh. Previously moths had been recorded by visitors on short stays. Their book recorded 213 species of macro moths, 171 species of micro moths and 28 species of butterflies. The list below is taken from Hicks and Hale (1998) with additional records referenced.
Butterflies.
"A Cornwall Butterfly Atlas" published in 2003 listed 26 species of butterflies recorded on the islands. Eleven are resident or likely to be resident.
Species list is taken from "A Cornwall Butterfly Atlas" with additional information referenced on the species account.
Hymenoptera.
Ants.
Fourteen species of ants have been recorded and ten are currently found.
Coleoptera (beetles).
In 1931 Kenneth Blair published a list of over 500 beetles, collated from collections and published papers. Below is listed some of the species a visitor is likely to see on a visit.
Amphibians.
The common frog ("Rana temporaria") is known from Tresco and Higher Moor, Lower Moor and Porthloo on St Mary's. Bones were identified from a 10th- to 13th-century site at Lower Town, St Martins. Giant, albino tadpoles, suffering from a mineral deficiency, resulting in a form of gigantism were found in the pool on the cricket pitch, also on St Martin's. Bones of a toad were found from a 17th-century occupation site at Steval Point Battery, St Mary's.
Birds.
As of September 2015 the number of species of birds' recorded is 437, with two, Moltoni's warbler ("Sylvia subalpina") (2014) and cedar waxwing ("Bombycilla cedrorum") (2015), awaiting confirmation from the British Ornithologists' Union Records Committee.
Reptiles.
Slowworms ("Anguis fragilis") have been present around Great Popplestone Bay on Bryher since the 1960s.
Mammals.
The "Mammals of Cornwall and the Isles of Scilly", an atlas published by the Cornwall Mammal Group lists 56 species for Cornwall and the Isles of Scilly, but most of the mammals found in Cornwall are missing from the islands. These include European badger ("Meles meles"), red fox ("Vulpes vulpes"), stoat ("Mustela erminea"), weasel ("Mustela nivalis") and most other small mammals such as the voles.