Background The Humberhead Peatlands NNR, located northeast of Doncaster, Yorkshire, is the UK’s largest lowland raised bog complex. It is part of the Natura 2000 network, consisting of several sites in two neighbouring areas: Thorne Moors (including the Goole & Crowle Moors) and Hatfield Moors. These sites are breeding sites for European nightjar (Caprimulgus europaeus). Over the years, however, large amounts of peat have been removed from the edges of the central areas of these moors, changing their topography. Peat-forming vegetation only grows if water levels are within +/- 20 cm of the peat’s surface. However, the topographic changes mean achieving such a hydrological balance is a challenge. Water needs to be more efficiently drained from the milled areas during peak rainfall, while there is also a need for terracing across the peatlands to retain water during dry periods. In some areas, on older peat cuttings, work is also required to remove scrub and raise water levels to around ground level. Objectives The main objectives of the Restoring Humberhead Peatlands project are to: Carry out conservation actions to restore lowland raised bog habitats and to establish a stable water table within +/- 20 cm of ground level across 3 273 ha, thus enabling peat-forming vegetation to re-establish on degraded peat bog surfaces; Link up areas of good quality habitat by increasing the general quality of the moors, allowing species to move between quality patches; Create large areas of bog habitat in favourable condition, ensuring suitable conditions for key species despite increasingly varied climatic conditions; Increase the European nightjar population by 15% from the current population of 80-88 territorial males; and Monitor bog recovery by water-level, data-logging and recording the re-establishment of peat-forming vegetation, and assess numbers of breeding European nightjar and key invertebrates. Expected results: 234 ha scrub removed on Hatfield Moors and 338 ha of invasive birch and rhododendron scrub removed on Thorne Moors, enabling the water table to rise to within 20 cm of the peat’s surface and allowing peat-forming vegetation to re-establish, achieving favourable Natura 2000 site conditions; 65 weirs, 67 peat dams and 5 800 m of bunds installed on Hatfield Moors to establish hydrological control; 16 tilting weirs, 225 peat dams, 7 900 m of bunds installed, and 2 300 m peat ‘cliff’ re-profiled on Thorne Moors to establish hydrological control; Installation of an automatically operated pumping station on Thorne Moors to prevent flooding, which would prevent peat-forming vegetation from re-establishing; Changes to European nightjar feeding patterns and a 15% population increase from 80-88 males to 92-101 males; Assessment of invertebrate populations in response to restoration; and Installation of additional water-level, data-loggers to monitor water levels.