The reservoir is important as it acts as a refuge for large numbers of wintering ducks, particularly mallard, shoveller, teal, wigeon, pochard, tufted duck and goldeneye. The area is of national importance for its summer populations of moulting pochard, tufted duck and common tern. The marginal vegetation supports many breeding bird species.
Around the margins of the reservoir are large marshy areas where many species of marsh plants flourish, including reedmace, reed canary grass and various sedges.
Warblers are attracted in spring, including sedge warbler, reed warbler, garden warbler, chiffchaff, black cap and willow warbler. There is a small reed warbler colony and twenty species of butterfly and fourteen species of dragonfly have been recorded.
The site is leased from Veolia Water.
The Trust's work at Hilfield Park Reservoir
The management regime is designed to encourage diversity of species.
Other management includes a major woodland programme - the existing conifer woodland has been thinned and many new native species planted.
