The Idle Valley Nature Reserve, which is managed by Nottinghamshire Wildlife Trust (NWT) is the largest of the trust's reserves in Nottinghamshire. The eastern boundary is created by the natural path of the River Idle; redundant gravel quarries to the west of the river have created wetland areas which comprise the majority of the site. The reserve contains many different habitats over 450 hectares, with 300 hectares being designated with SSSI status. It is the largest wetland area in Nottinghamshire and over 250 species of birds have been recorded there making it one of the top birding sites in the UK. The reserve is known for spectacular starling murmations. NWT has a program of activities and events for the benefit of schools, community groups and individuals and is becoming increasingly popular with established walking groups in the area and also neighbouring counties.