The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Range & Status
Palearctic; in Britain and Ireland 470 pairs breed; 85,500 winter.
Cornwall: a winter visitor and passage migrant to inland waters, some summer (possibly an occasional breeder on the moor, but never proven). Numbers fluctuate with severity of weather but total some 400 in recent winters; Loe Pool is the main site with up to 175; 30-50 are regularly seen at Stithians, Colliford, Dozmary Pool and Siblyback. Isles of Scilly: small numbers in winter, chiefly Tresco.
Habitat & Ecology
Freshwater lakes and reservoirs, locally on upper reaches of estuaries (especially in cold weather).
Protected under Schedule 2, Part 1 of the Wildlife and Countryside Act 1981 and Annexes 11/1 and 111/2 of the European Union Conservation of Wild Birds Directive. Listed (long list) as a globally threatened/declining species (BSGR, 1995). Most sites are SSSI.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.