The few natural lakes and many reservoirs in the North Pennines provide food and shelter for a number of different species.
Large gatherings of gulls can often be seen, in particular black headed gull and common gull. These birds feed on nearby fields and roost on the open water.
Where lakes or reservoirs have significant amounts of fringing vegetation, nest sites and shelter are provided for species such as the sedge warbler and reed bunting.
Open water can also provide roosting and feeding areas for wildfowl like mallard, teal, coot, moorhen, tufted duck, pochard and goosander. In the winter, visitors from more northerly climes such as the goldeneye, wigeon and whooper swan may be found.