The reserve is best known for its birds. The area is an important site for winter wildfowl and often holds a high proportion of the County’s shoveler and diving ducks, with larger numbers of mallard, teal, and occasionally wigeon. Scarcer wildfowl such as sawbills and sea ducks are recorded regularly and cormorants are common. All the British grebes have been recorded. In the spring and autumn, many migrants birds pass through and the delta area attracts a wide range of waders in small numbers. In the summer, the breeding birds include great crested grebe, shelduck, little ringed plover and common tern. A substantial population of reed and sedge warblers, and some rarer species such as grasshopper warbler, may also be present.