Blagdon Lake

Also within

Somerset County Mendip Hills Scenic Area

Condition (Natural England)

Habitats

Carr

Birds & fish recorded

Birds

Fish

Description

Area, 212.7 ha. 525.6 ac. Description This site consists of a large freshwater reservoir with peripheral areas of reed bed, carr, woodland and natural grassland. Blagdon Lake has an average depth of only 5m, reaching 13m at its deepest point. The moderately nutrient rich and alkaline waters stratify during the summer, but have not been known to develop dense algal blooms. The Lake floor has a diverse invertebrate fauna characteristic of well oxygenated conditions, with snails and water beetles particularly well represented. Of special interest is the local dragonfly, the ruddy darter Sympetrum sanguineum. Fish present include three spined stickleback Gasterosteus aculeatus, eel Anguilla anguilla and gudgeon Gobio gobio. Brown trout Salmo trutta fario and rainbow trout Oncorhynchus mykiss are stocked. Blagdon Lake supports large numbers of wintering waterfowl. There are nationally important populations of teal Anas crecca up to 2,000 and large numbers of mallard Anas platyrhynchos 1,000, tufted duck Aythya fuligula 425, pochard Aythya ferina 750, wigeon Mareca penelope 1,000 and coot Fulica atra 1,150. gadwall Mareca strepera, pintail Anas acuta, shoveler Spatula clypeata, goldeneye Bucephala clangula, ruddy duck Oxyura jamaicensis, Bewick's swan Cygnus columbianus, great crested grebe Podiceps cristatus and little grebe Tachybaptus ruficollis winter in smaller numbers. 57 species of breeding bird have been recorded, including mallard, shoveler, tufted duck, coot, moorhen Gallinula chloropus, great crested grebe and little grebe, with reed bunting Emberiza schoeniclus and sedge warbler Acrocephalus schoenobaenus nesting in fringing vegetation. A meandering shoreline over 11 kilometres provides sheltered bays with stands of reed sweet grass Glyceria maxima, reed canary grass Phalaris arundinacea and common reed Phragmites australis. Aquatic plants of particular interest include flowering rush Butomus umbellatus and shoreweed Littorella uniflora. Neutral grasslands bordering the Lake support a species rich meadow flora, with saw wort Serratula tinctoria, wild carrot Daucus carota and pepper saxifrage Silaum silaus.

Species mentioned

Insects to look out for

These moths, butterflies and beetles are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

Host-plant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.