reach Britain until the rising sea level once again isolated the islands. Great Britain was cut off from mainland Europe in around 8,200 BP by the Storegga Slide tsunami flooding Doggerland. Extinctions in Britain over the period have thus had three main causes: Climate change as the ecosystem swung from temperate woodland and pasture, through open mammoth steppe to uninhabitable polar desert, and back. Habitat loss brought about by human activities, such as the clearing of woodland or draining of marshland. Hunting by humans. It is important to remember that absence of evidence is not evidence of absence; the fossil record is always incomplete; and many of the early dates are very approximate, since caves in Britain were often excavated before modern archaeological stratifications and dating techniques. Key † - A species that is globally extinct * - A species that is known to have been introduced by humans and was never present by natural immigration. Some animals have gone extinct several times and then recolonized. The date given is of the most recent extinction. Species that have been introduced or reintroduced by humans are noted. Mammals Birds Common crane – late medieval period (re-established) Dalmatian pelican – c. 1000 B.C. Gadfly petrel (unknown Pterodroma species, presumed Fea's petrel) – Iron Age Eurasian spoonbill – 17th century (as a breeding bird) (re-established) †Great auk – 1844 Great bustard – 19th century (reintroduced) Kentish plover – 20th century (last breeding record 1979) Little egret – late medieval period (re-established) Pied avocet – 19th century (re-established) Red-backed shrike – 1989 (as a regular breeding bird)] Western capercaillie – 1780s (reintroduced) Hazel grouse – Last Glacial Period and only found in South West England White stork – 1416 (reintroduced) Wryneck (as a regular breeding bird) White-tailed eagle – 1916 (reintroduced) Lanner falcon - 1236–1300 (change of climate Western marsh harrier – late 19th century (re-established) Northern goshawk – late 19th century (re-established) Red kite - 1870s (England), 1886 (Scotland), (reintroduced) Osprey – 1916 (re-established) Eurasian eagle owl - c. 8000 BP (re-established) Boreal owl - went extinct in mainland Britain due to change of climate after Last Glacial Period. Northern hawk owl - went extinct in mainland Britain due to change of climate after Last Glacial Period. Snowy owl - went extinct in mainland Britain due to change of climate after Last Glacial Period Fish Burbot – A fisherman caught the last recorded