Mystery as Britain's biggest inland bird colony vanishes into thin air

A A A

Britain's biggest inland bird colony has vanished almost without trace, leaving wildlife experts baffled.

Britain's biggest inland bird colony has vanished almost without trace, leaving wildlife experts baffled.

Up to 50,000 adult and young black-headed gulls would gather at Sunbiggin Tarn in Cumbria until two years ago, in a vast avian metropolis that spread over 10 acres - but now only a few score pairs are left.

For no obvious reason, nearly all the 25,000 adult birds seem to have taken a sudden dislike to this lake in a moorland basin 1,228ft above sea level in the Pennines west of Kirkby Stephen - and left.

"It's a mystery - we don't know why they went or where they've gone," said Geoff Longrigg, a local farmer and keen ornithologist who has studied the colony over many years.

"Such a massive number of nesting black-headed gulls is very rare and something that doesn't escape attention, so if another colony on that scale had become established elsewhere recently I'm sure we'd have heard about it.

"Perhaps they've just become dispersed among the many small colonies scattered about the Pennines and elsewhere. There's certainly no evidence to suggest they've suffered some major disaster."

What adds to the puzzle is the element of déjà vu. One of Europe's largest black-headed gull colonies used to be at the mouth of the river Esk, near Ravenglass, 40 miles to the west - then it disappeared in the 1980s, many of the birds possibly switching to Sunbiggin, which was already established.

David Baines, a local game conservancy researcher, said: "The end of the Ravenglass colony was also a mystery - it even led to checks for radioactive contamination with Sellafield being near by. But that was ruled out and no other reason was found.

"I don't think predation was a problem at Sunbiggin. Foxes regularly took eggs and young but the colony was so big it had no effect - in the same way there was no impact from gypsies filling a few buckets with eggs for food.

"The impression is that the gulls have suddenly, collectively, decided they needed a change of scene. What triggered that is something we don't know, despite this having occurred twice in Cumbria in 20 years. Perhaps we never will know what happened."

Mr Baines has vivid memories of the colony over the past 25 years. He would often take part in operations to fit rings to the legs of young birds to record their movements.

"There is nothing like the experience of walking into the centre of the colony with thousands of birds flying around, screeching loudly and dive-bombing. It's quite weird seeing it virtually deserted now."

The black-headed gull, Larus rudibundus, has not always been so common in Britain - its numbers declined so much during the 19th century that extinction was feared during the 1880s.

The population revived after legal curbs were introduced on shooting and egg harvesting. Studies during the 1980s put the number nesting on the coast at 82,000 pairs, with possibly 130,000 pairs inland.

PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Tradewind Recruitment: Geography Teacher

£90 - £140 per day: Tradewind Recruitment: On behalf of a successful academy i...

Investigo: Finance Business Partner

£45000 - £50000 per annum: Investigo: My client, a global leader in providing ...

Austen Lloyd: Commercial Property Solicitor - West London

Excellent Salary: Austen Lloyd: WEST LONDON - An excellent new opportunity wit...

Recruitment Genius: Florist Shop Manager

£8 - £10 per hour: Recruitment Genius: A Florist Shop Manager is required to m...

Day In a Page

Syria crisis: Celebrities call on David Cameron to take more refugees as one young mother tells of torture by Assad regime

Celebrities call on David Cameron to take more Syrian refugees

One young mother tells of torture by Assad regime
The enemy within: People who hear voices in their heads are being encouraged to talk back – with promising results

The enemy within

People who hear voices in their heads are being encouraged to talk back
'In Auschwitz you got used to anything'

'In Auschwitz you got used to anything'

Survivors of the Nazi concentration camp remember its horror, 70 years on
Autumn/winter menswear 2015: The uniforms that make up modern life come to the fore

Autumn/winter menswear 2015

The uniforms that make up modern life come to the fore
'I'm gay, and plan to fight military homophobia'

'I'm gay, and plan to fight military homophobia'

Army general planning to come out
Iraq invasion 2003: The bloody warnings six wise men gave to Tony Blair as he prepared to launch poorly planned campaign

What the six wise men told Tony Blair

Months before the invasion of Iraq in 2003, experts sought to warn the PM about his plans. Here, four of them recall that day
25 years of The Independent on Sunday: The stories, the writers and the changes over the last quarter of a century

25 years of The Independent on Sunday

The stories, the writers and the changes over the last quarter of a century
Homeless Veterans appeal: 'Really caring is a dangerous emotion in this kind of work'

Homeless Veterans appeal

As head of The Soldiers' Charity, Martin Rutledge has to temper compassion with realism. He tells Chris Green how his Army career prepared him
Wu-Tang Clan and The Sexual Objects offer fans a chance to own the only copies of their latest albums

Smash hit go under the hammer

It's nice to pick up a new record once in a while, but the purchasers of two latest releases can go a step further - by buying the only copy
Geeks who rocked the world: Documentary looks back at origins of the computer-games industry

The geeks who rocked the world

A new documentary looks back at origins of the computer-games industry
Belle & Sebastian interview: Stuart Murdoch reveals how the band is taking a new direction

Belle & Sebastian is taking a new direction

Twenty years ago, Belle & Sebastian was a fey indie band from Glasgow. It still is – except today, as prime mover Stuart Murdoch admits, it has a global cult following, from Hollywood to South Korea
America: Land of the free, home of the political dynasty

America: Land of the free, home of the political dynasty

These days in the US things are pretty much stuck where they are, both in politics and society at large, says Rupert Cornwell
A graphic history of US civil rights – in comic book form

A graphic history of US civil rights – in comic book form

A veteran of the Fifties campaigns is inspiring a new generation of activists
Winston Churchill: the enigma of a British hero

Winston Churchill: the enigma of a British hero

A C Benson called him 'a horrid little fellow', George Orwell would have shot him, but what a giant he seems now, says DJ Taylor
Growing mussels: Precious freshwater shellfish are thriving in a unique green project

Growing mussels

Precious freshwater shellfish are thriving in a unique green project