RSPB Dearne Valley Old Moor is an wetlands nature reserve in the Dearne Valley near Barnsley, South Yorkshire, run by the Royal Society for the Protection of Birds (RSPB). It lies on the junction of the A633 and A6195 roads and is bordered by the Trans Pennine Trail long-distance path. Following the end of coal mining locally, the Dearne Valley had become a derelict post-industrial area, and the removal of soil to cover an adjacent polluted site enabled the creation of the wetlands at Old Moor. Old Moor is managed to benefit bitterns, breeding waders such as lapwings, redshanks and avocets, and wintering golden plovers. A calling male little bittern was present in the summers of 2015 and 2016. Passerine birds include a small colony of tree sparrows and good numbers of willow tits, thriving here despite a steep decline elsewhere in the UK. Barnsley Metropolitan Borough Council created the reserve, which opened in 1998, but the RSPB took over management of the site in 2003 and developed it further, with funding from several sources including the National Lottery Heritage Fund. The reserve, along with others nearby, forms part of a landscape-scale project to create wildlife habitat in the Dearne Valley. It is an 'Urban Gateway' site with facilities intended to attract visitors, particularly families. In 2018, the reserve had about 100,000 visits. The reserve may benefit in the future from new habitat creation beyond the reserve and improved accessibility, although there is also a potential threat to the reserve from climate change and flooding. Landscape Most of the Dearne Valley area lies on the coal measures, comprising Carboniferous sandstone and slate with seams of coal. The valleys contain fertile alluvium deposited by their rivers, and the sandstone forms rolling ridges cut by the broad floodplains. The area has been settled continuously since prehistoric times, with villages developing on the drier sandstone ridges above the flood plain from at least the late Saxon period. Mining is recorded from at least the 13th century, and probably back to Roman Britain, and the area became heavily industrialised in the 18th century with the arrival of the Dearne and Dove Canal. This connected Barnsley to the River Don and beyond, aiding the intensive exploitation of the locality's coal, sandstone and iron ore. Over the next two centuries, especially following the arrival of the railway in 1840, the area became dominated by its heavy