Hen harriers raised five chicks in Tynedale in 2007
A round-the-clock security operation is under way to protect a pair of rare birds of prey that have returned to a nesting site in Northumberland.
Last year a pair of hen harriers raised five chicks at a nest in Tynedale, which was guarded 24-hours a day.
Now the RSPB and Forestry Commission have mounted a similar exercise after a pair of the birds returned to the site.
Hen harriers are one of England's rarest birds, with only 15 successful nests recorded by the RSPB in 2007.
More than 30 volunteers are helping to watch over the Northumberland birds.
The harrier "task force" is equipped with high-powered cameras and night vision equipment. Other security measures are in place in the area where the birds are nesting.
Harrier Watch co-ordinator Phil Curtis, said: "The English hen harrier population is perilously low, so every one of these rare birds is precious and it's wonderful news that a pair of these magnificent birds of prey is nesting in Northumberland."
The Northumberland Harrier Nest Watch is a partnership between the RSPB, and Forestry Commission with support from the Northumberland and Tyneside Bird Club.
Tom Dearnley, Forestry Commission ecologist, added: "It's terrific news that the birds are back in Northumberland.
"Now the hard work starts in earnest to protect them and do all we can to allow chicks to fledge successfully."