Sea bird populations on St Kilda are being profoundly affected by climate change

The Guardian reports, 4th December 2015: The survival of seabirds including puffins and kittiwakes on St Kilda — the island archipelago home to one of the world’s most important seabird populations — is being threatened by climate change, striking new evidence shows.

Sea bird populations on

Naturalists have discovered that the kittiwake, a small migratory gull with ink-black wing tips, is on the brink of disappearing from St Kilda. The remote cluster of Scottish islands in the eastern Atlantic is the UK’s only place with two Unesco world heritage site listings — for its culture and natural history — and one of only 24 sites with a dual listing worldwide.

The kittiwake did not breed in St Kilda this season, with just one chick born there this year after a 99% decrease in occupied nests since the 1990s. Its adult population has since halved. The number of fulmar chicks has plunged by 33% since 2005, while St Kilda’s puffin population is in persistent decline.

Warming seas to the west of the Hebrides are believed to have driven the marine life the birds rely on further north into colder seas or deeper into the water, starving the birds of food.

The findings from the annual bird survey by the National Trust for Scotland, the charity which owns St Kilda, have alarmed conservationists.

“This data from St Kilda is really extremely worrying,” said Dr Paul Walton, head of habitats and species in Scotland for the Royal Society for the Protection of Birds. “We are losing whole colonies of these birds now and it’s a very serious issue. Frankly, it breaks my heart, it really does.”

St Kilda – now regarded as one of the world’s most significant bird sanctuaries — was once inhabited by an isolated and beleaguered community whose songs and poetry heavily featured the seabirds they subsisted on before moving off the archipelago in 1930.

It lies about 41 miles (66km) west of the Hebrides. When bird populations are at their highest, about 1 million birds perch on the island’s high, precipitous cliffs, sea stacs and rocky crags, hosting the world’s largest gannet colony and nearly a third of the charismatic Atlantic puffins that live around the UK and Ireland.

In 1987, the National Trust for Scotland (NTS) counted 7,829 kittiwakes on the islands. Now that number stands at 3,886. When routine monitoring began 21 years ago, there were 513 occupied kittiwake nests there, with 56 chicks born. This year, researchers found just four nests, a 99.2% decrease, and a single chick.

The number of fulmar nests has declined by 37% since 2002, with productivity rates well below normal levels, averaging 0.28 chicks per nest compared with 0.42 in 2005.

Puffin numbers are also struggling. At 0.59 chicks per burrow, the NTS says puffin breeding is “still below the long-term average and, set against the long time scale of the decline, suggests conditions are becoming less suitable for breeding”.

Source: The Guardian, 4th December 2015. For the full text, see www.theguardian.com/environment/2015/dec/04/climate-change-threatening-puffins-kittiwakes-seabirds-st-kilda-scotland


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