Abstract The bittern, Botaurus stellaris L., is a cryptic, fish-eating, reedbed bird that was once widespread and common across the UK. It became extinct in 1886, only to return two decades later. After increasing to a peak of 80 booming males in 1954, the population declined to only 11 in 1997, and a second extinction in the UK seemed likely. In conjunction with partner organisations, the Royal Society for the Protection of Birds has undertaken research to determine the food and habitat needs of bitterns to support a major programme of work to reverse the fortunes of bitterns in the UK. Existing sites have been managed to increase populations of key prey species, notably European eel, Anguilla anguilla (L.) and rudd, Scardinius erythrophthalmus (L.), by increasing access into reedbeds along expanded gently-shelving littoral zones, and by addressing issues relating to connectivity, water quality, zooplankton and macrophytes. Degraded sites have been also rehabilitated and new sites created. The project was successful, with an increase to 55 booming males in 2004, exceeding the target 6 years ahead of schedule. The reedbed works also benefited a wide range of other wetland species.