It is best known for its wetland breeding birds, including Great Bittern, Western Marsh Harrier, Pied Avocet and Bearded Reedling. It forms part of the Minsmere - Walberswick Special Protection Area which includes a large swathe of coastal land from the estuary of the River Blyth southwards to the Minsmere River.
In September 2004 a moth species, Catocala conjuncta (Esper), previously unrecorded in Britain was found on the reserve. To acknowledge its place of capture it was given the common name Minsmere Crimson Underwing.