Arctic terns usually nest in coastal areas
A special nesting platform has been built for vulnerable birds visiting a Northumberland reservoir this summer.
Arctic and common tern, which normally nest along the coast, have been spotted at Northumbrian Water's Whittle Dene reservoir site, near Horsley.
Until recently the birds did not have anywhere suitable to nest but water company volunteers stepped in to build a nesting platform.
The reservoir is an important site for other species of water-loving birds.
Northumbrian Water's conservation officer Kelly Hollings said: "Our aim is to encourage the birds to set up home at Whittle Dene by providing nesting sites.
"We hope that this will add to the wealth of bird life that can already be seen across the nature reserve."
The four metre by two metre timber and polystyrene camouflaged platform is topped with gravel and is big enough for four to six breeding pairs.
Four species of tern - little, common, arctic and sandwich - have been identified as regionally important species in the North East biodiversity audit.
The Farne and Coquet Islands form the key sites for the birds, while Teesside contains the largest mainland colony of common tern in England.