Effects on shorebird numbers of disturbance, the loss of a roost site and its replacement by an artificial island at Hartlepool, Cleveland

Hartlepool West Harbour contains nationally important high water roosts for wintering shorebirds, including purple sandpipers Calidris maritima, turnstones Arenaria interpres and knots Calidris canutus. Redevelopment of the site, starting in summer 1991, replaced the dilapidated stone pier used formerly as the main roost site with a new pier and an island built specially for the birds. Maximum numbers of turnstone, oystercatcher Haematopus ostralegus and knot using the harbour have declined in the two winters since the development. Local changes in feeding numbers and national winter population tr ends of turnstone, oystercatcher and knot do not explain the size of the declines seen in their roosting numbers at West Harbour. An increase in disturbance, particularly from people and boats - a result of ina eased access and the creation of a marina - are probable causes. Purple sandpiper numbers at the West Harbour roost are falling due to a local population decline, perhaps associated with emigration from the area between winters. Despite these overall declines in the use of West Harbour, the island now forms the main roost site in the harbour for all species. Features of the design and construction of the island which may affect its attractiveness to shorebirds are discussed. (C) 1996 Elsevier Science Ltd