The Little Tern is in decline across the UK
The Army and RSPB have joined forces to help a struggling seabird survive at a Portsmouth nature reserve.
The little tern unwittingly nests on shore land which becomes submerged at high tide at Langstone Harbour.
Now 450 tonnes of shingle are being used to create a raised section on the small island where the birds will be safe from the threat of high tide.
The Army began the week-long operation on Monday but can only work at certain times due to the tide.
Staff Sergeant Stuart Barclay, of the Port and Maritime Regiment, said: "More often than not it is vehicles and ammunition which we discharge over the beach.
"We are just showing our adaptability to use this bit of kit for civilian purposes."
The little tern is on the RSPB's amber list of under threat birds.
In September, a study by the charity revealed 11 nests were built by the species last summer but bore no young.
About 450 tonnes of shingle will be deposited on the small island
Chris Cockburn, RSPB Langstone Harbour warden, said in 1995 about 100 pairs of little terns would have been seen on the reserve but that has barely reached double figures in recent times.
He said: "They are very busy birds, always hovering over the sea diving in getting food and coming back, they are fantastic.
"By raising the whole elevation of the beach there is a much better chance they will stay above these big tides we get."
He is expecting to see them back on the reserve from the middle of April.
The little tern is one of the rarest terns in the UK, with only 2,000 breeding pairs spotted a year.
The Army and RSPB join forces to help a struggling seabird survive at a Portsmouth nature reserve.