Reintroducing common cranes
Human ‘parents’ raised dozens of young cranes equipping them to feed and fend for themselves. Now in the wild, they range far and wide starting families of their own.
The challenge
The common crane was extinct here in Britain for 400 years. The last records date from the time vast wetland areas in the UK like the Fens were drained to grow crops. However, the memory of this magnificent bird lived on, with hundreds of British place names starting with Cran- or Tran- (the Norse for crane) dotted around the country.
In 1979 a few cranes from continental Europe settled in the Norfolk Broads in the east of Britain. Conservationists protected wetland habitat for them, but cranes breed slowly and the size of the group remained small.
Two decades later and it seemed as though the crane, despite being a well-loved totem for wetlands, would never live more than a marginal existence in this country.
What we are doing
WWT’s long history of breeding waterbirds for conservation gave us an idea. Could we take crane eggs from Europe where there are tens of thousands, and bring them to the UK to hatch and rear in safety before releasing them into the wild?
It was a daring concept. Cranes are intelligent and social creatures. Any contact with humans could affect their behaviour, leaving them imprinted on their carers and unable to survive in the wild. We developed special outfits to disguise the WWT people who were to train the cranes, and prosthetic crane heads so the young birds fixated on something recognisably crane-like.
Over five years we hatched and reared nearly 100 young cranes at our special ‘crane school’ at Slimbridge.
As hatchlings our disguised ‘crane parents’ exercised each bird separately because they are naturally aggressive to their siblings.
Once they’d matured a little, we socialised them as a group and taught them the basics of foraging, pointing out small creatures with the prosthetic crane heads for them to peck at.
Later, we taught them how to react to the threats of humans and foxes, with our ‘crane parents’ playing recorded crane alarm calls and role playing the act of flight.
At each stage the young cranes’ development was meticulously monitored to ensure they received the correct balance of nutrients and exercise for their long legs to grow straight and fast.
Key achievements
We released 93 young cranes at a secret location in the Somerset Levels and Moors over five years.
The cranes adapted to life in the wild more successfully that anyone predicted. All young birds face risks in the wild, but the cranes’ survival rate was much higher than expected.
As the cranes matured, many have paired up and settled down to breed. Cranes rarely breed before they are four years old, and it may take several attempts before they succeed in rearing a chick. But by the end of 2018, we have had more than 50 nesting events from which 18 chicks have successfully fledged.
The bulk of the crane population is still centred on the Somerset Levels and Moors, but the birds range far and wide. Tracking devices have given us detailed insight into their movements. They appear to use the Severn Vale as a regular route, and a large group has set up semi-permanent home at WWT Slimbridge in Gloucestershire. They have also been as far as Staffordshire in the north, Glamorgan in the east, Devon in the south and all the way to Suffolk in the east.
During the same period the population in eastern Britain has boomed, with pairs settling further up the east coast, even as far north as Scotland. Birds from the reintroduction project in the west have mixed with the eastern birds, and there’s even been one attempt to breed.
In 2019, 56 pairs were recorded across the UK. Of these, up to 47 pairs attempted to breed and they raised 26 chicks. The total population is now believed to be over 200 birds - a new record.
The cranes are also a catalyst for creating new wetlands. Cranes need wetlands in order to breed in safety from ground predators such as foxes. Areas of land across Somerset and in Gloucestershire have already been enhanced to help the cranes, and in helping the cranes the new habitat will also help other ground-nesting wetland birds.
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Partners and funders
The Great Crane Project is a partnership between WWT, RSPB and Pensthorpe Conservation Trust, with major funding from Viridor Credits Environmental Company. Its aim is to restore healthy populations of wild cranes throughout the UK, so that people can once again experience these beautiful birds.
