If you go down to the castle at night, you're sure of a big surprise.

Thirlwall Castle takes its name from Hadrian's Wall, which supplied some of the stone it was fortified with in the 14th century. Originally the home of the Thirlwall family, it was abandoned by them as a residence in the 18th century and passed through various hands until it was taken over by the Northumberland National Park Authority. Despite the castle falling into disrepair 400 years ago, work continues to save the scheduled monument for generations to come, and for the wildlife which calls it home.

An edition of the Tyne Tees Television wildlife programme Wild North, presented by Jonathan Morrell. In the first part of the programme a report from Thirlwell Castle near Greenhead in Western Northumberland where consolidation work being carried out there by the Northumberland National Park won't affect the wildlife living there.

The second report looks at the research being carried out along the Tees Estuary on the affect the Tees Barrage may have had on the mud flats and bird life in the area. In the second part a report looking at work being done in the region by Red Squirrel Northeast to protect and monitor the native Red against the invading Gray Squirrel. The final report from a pond at Eaglescliffe and the Great Crested Newt.