Location and Topography
Oldham lies in the north east of the county and borders West Yorkshire to the east. It contains the highest land in Greater Manchester, rising to 542 m above sea level (asl) at Black Chew Head on Saddleworth Moor. There are also low-lying areas along the river valleys in the south and west of the borough down to 75 metres above sea level.
The eastern half of Oldham supports spectacular tracts of moorland (upland heath and blanket bog), much of which lies within the South Pennines Moor SPA and Peak District National Park. This area contains over a third of the county's wet heath. Major upland reservoirs at Castleshaw and Dovestone add to the diversity of habitats.
The rivers Medlock, Irk and Tame have their sources high up in the Pennines and provide important corridors for wildlife to move through, as they flow through the borough. Oldham has significant areas of both unimproved and semi-improved acid grassland.
The stretch of the Rochdale canal that runs through the borough has been designated as a Site of Special Scientific Interest (SSSI) and a Special Area for Conservation (SAC).
The moorland supports important numbers of breeding upland birds, including a significant proportion of the county's Golden Plover, and is also home to a small population of Mountain Hares. Ravens have recently returned to the borough's high land. They can be located by their gruff calls and can be seen in late winter performing their spectacular aerial displays.
Roe Deer are an increasingly common site in the woodlands and Badger, Fox, Stoat, and Weasel add to the variety of mammals to be found in Oldham.
Every spring large numbers of Common Toads head towards the ponds and lodges in the Uppermill area to spawn. Oldham's ponds also support three species of Newt as well as the Common Frog. Extensive conifer plantations provide a habitat for specialist species of bird and fungi.
The Oldham section of the Rochdale Canal supports the European Protected Species floating water plantain (Luronium natans). White-clawed crayfish and American pondweed (Potamogeton epihydrus), a red data book species, also occur. The UK Biodiversity Priority Species Grasswrack Pondweed is found in the Huddersfield Narrow canal SSSI.
Improvements in habitat management at Daisy Nook have resulted in an increase in Orchids, relocated when the M60 was extended.