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The reservoir, which has an area of 105.4 hectares (260 acres) is attractive to waterbirds; in particular wintering wildfowl and gulls.
Wildfowl present regularly in winter include Mallard, Gadwall (Anas strepera), Tufted Duck, Pochard(Aythya ferina), Wigeon, goldeneye (Bucephala clangula) and Goosander. A large flock of Coot is present, and Great Crested Grebe (Podiceps cristatus) is also numerous.
Because of its proximity to the Bristol Channel, storm-blown seabirds are occasionally found here, including Shag, Grey Phalarope, and divers and grebes.
A number of rare and scarce birds have been seen at Cheddar Reservoir. These include: