Donna Nook National Nature Reserve covers more than 10 km (6.25 miles) of coastline between Grainthorpe Haven in the north and Saltfleet in the south where it borders the Saltfleetby-Theddlethorpe National Nature Reserve.
The reserve consists of dunes, slacks and inter-tidal areas. Coastal processes, particularly sand and mud accretion, alter the natural features from year to year, and sand from the beach and offshore sandbanks is blown inland by easterly winds to form dune ridges. Deposition of material from the River Humber has resulted in mudflats and saltings. The advancing dunes have trapped areas of saltmarsh behind them, and these areas have gradually become less saline, allowing an interesting plant community to develop. On the landward side, the reserve is bounded by a sea bank erected after the floods of 1953. The reserve is rich in bird life: 47 species of bird breed regularly and the area is famous for more uncommon passage migrants and rarities; over 250 species have been recorded in total.
Visitors should be made aware that the Ministry of Defence still maintains part of the area as a bombing target range and under no circumstances should anyone enter the bombing area when red flags are flying. However, most of the dune area is accessible at all times.
For much of the year grey seals at the Lincolnshire Wildlife Trusts’ Donna Nook National Nature Reserve are at sea or hauled out on distant sandbanks. Every November and December, the seals give birth to their pups near the sand dunes: a wildlife spectacle which attracts visitors from across the UK.
Further information about visiting during the seal pupping season can be seen here: Viewing seals at Donna Nook