The birds are a metre high and live in wetland habitats
A bird species that vanished from the East Anglian fens 400 years ago is nesting at an RSPB reserve in Suffolk.
The Royal Society for the Protection of Birds (RSPB) said two young cranes had been seen at Lakenheath Fen.
Officials said the development followed the launching of a project aimed at re-establishing cranes in Britain.
The fens, which once stretched from Cambridge to Lincoln, were the last stronghold of the three-foot (1m) high bird before it became extinct in 1600.
Conservationists said the bird vanished as wetlands were drained and hunting took its toll.
The Great Crane Project, which aims to establish a sustainable population of cranes in Britain, starts with taking eggs from healthy populations overseas.
Common Crane (Grus Grus)
Global population: 220,000
The eggs are then incubated, the chicks nurtured and then released into a protected environment.
An RSPB spokesman said: "Cranes have nested in the Norfolk Broads in recent years and have made sporadic attempts elsewhere.
"But the Fens are significant because they were traditionally the stronghold of the crane and we have really been hoping that they would return to the area."
Lakenheath Fen was created out of carrot fields in the early 1990s in an effort to encourage wetland birds to return.
Norman Sills, site manager at the reserve, said: Seeing young cranes fly over the reserve makes me realise all our hard work has been worthwhile.
"These are fantastic birds."