South Walney Nature Reserve comprises the southern end of Walney Island, off the coast of Barrow in Furness in Cumbria. It has been managed by Cumbria Wildlife Trust since 1963, and forms part of the South Walney and Piel Flats SSSI. It is also part of the Morecambe Bay and Duddon Estuary Special Protection Area (SPA) for breeding and wintering lesser black-backed gulls. The reserve holds a large colony of lesser black-backed and herring gulls, as well as smaller numbers of great black-backed and black-headed gulls, and this gull colony forms a feature of the SSSI. The lesser black-backed gull colony at South Walney used to be one of the largest in the UK, with numbers in excess of 20,000 in the 1990s, and used to extend over an area of dunes referred to as gull meadow and on The Spit . The colony continues to decline and in 2020 reduced to around 1,000 pairs restricted to The Spit. Mammalian predation is considered to be one of the factors for the decline in this colony, and efforts are underway with plans to expand and strengthen the predator proof fencing.