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22 Jun 2018

A million seabirds, but for how long?

St Kilda
In days gone by, the seabirds of St Kilda were caught for food. Now they’re under threat from a far greater force – climate change.

Air rushes past my face so fast it feels like someone has thrown a rock in my direction.

‘What the devil …?’ asks my companion, who is walking with me up to the top of the sea cliffs from the village below. We stop, look and listen. WHOOSH! It comes again, this time distorting the atmosphere so close to my nose that I actually step backwards.

I’m on Hirta, the main isle of the St Kilda archipelago, the furthest-flung of all of Britain’s western isles. And what I’m experiencing is the sensation of being dive-bombed by a pair of resident great skuas.

From Harris even the fastest passenger boats take almost three hours to reach these islands, which also include Boreray, Soay and Dun. From here, were you to continue west, the next piece of land you’d encounter would be Canada’s Torngat mountains. A helicopter brings post to St Kilda each week, but that too can be delayed due to the notoriously changeable weather.

Large rock at St Kilda
The sea stacks and islands of St Kilda are home to the largest colony of seabirds in Europe

The archipelago, one of 400 islands and islets looked after by the Trust, is home to nearly a million seabirds, the largest colony of its kind this side of the Atlantic. Not only that, but it also has its own subspecies of wren, the endemic Soay sheep and a subspecies of mouse that’s twice the size of your regular British fieldmouse. St Kilda is the UK’s only UNESCO World Heritage Site that’s recognised for both its natural and cultural significance – one of just 35 in the world. But the lifeblood of St Kilda, as with many of our islands and coastlines, is under threat. We need your help to protect them.

Inhabited by humans since the Bronze Age, St Kilda was once a community of hardy souls who thrived on a diet of protein-rich seabirds and their eggs. Every year the islanders would climb down the cliffs, a perfect home to millions of birds, to reach this seemingly endless food source. They’d take their catch back to hand-built stone cleits (which I pass as I hike – most are still intact) and dry out the birds’ meat to sustain them during the winter months.

St Kildans
The former residents of St Kilda thrived on birds and their eggs for centuries

This was sustainable living, St Kilda-style. But as the 20th century began, the world crept closer, and the place in the sea that had been home to these families for so long became an impossible place on which to survive. Voluntarily, the remaining full-time residents evacuated Hirta in 1930. The birds were left to rule the roost.

Since 1956, the Trust has looked after the place, with our experts maintaining and monitoring its heritage and wildlife. In the last three decades, however, the winged guardians of this amazing archipelago have faced a problem. ‘For the second consecutive year, only one kittiwake was identified in seven of our monitoring plots’, wrote Gina Prior, the Trust’s seabird and marine ranger on St Kilda in her 2017 report. ‘A single egg hatched but failed to fledge. This is a significant decline from a high of 513 nests in 1994 when monitoring began.’

I speak to Susan Bain, property manager of St Kilda. ‘There was a massive lump in my throat when I first read Gina’s reports’, she says. ‘What we are seeing is a long-term decline, which is worrying on all sorts of levels.’ And it’s not just the kittiwakes – while their decline is the most dramatic, other species on the archipelago are under threat too, with the Atlantic puffin creeping dangerously near to the endangered list. What’s happening?

‘They may be dying out because they are failing to breed or physically dying of starvation’, says Dr Richard Luxmoore, Senior Nature Conservation Adviser at the Trust. ‘Seabirds spend most of their time at sea and bring back food to their chicks, so when food supplies decline or move it has a noticeable impact.’ Carbon emissions around the world have caused sea temperatures to rise, and warming waters mean food sources such as sand eels and plankton, which need cooler temperatures, are shifting north – too far for many seabirds to fly.

Quote
“If one species is affected then it will have a knock-on effect on others, including ourselves. We need to take heed.”
Susan Bain
Property Manager of St Kilda

Scotland is home to 45% of Europe’s breeding seabirds, and one-fifth of them nest on land looked after by the Trust – more than any other conservation group in the country. That’s why, by supporting our work, you can help us protect Scotland’s seabirds and the islands and coastlines they inhabit.

‘Seabirds are part of life on St Kilda’, says Susan. ‘They’re bound up in its archaeology and history, and with them, that’s disappearing. If it were a building, or a monument under threat, we wouldn’t let that happen.

‘The loss of the seabirds will have impacts that we don’t even know until they take place – they are pieces of a unique and fragile ecosystem.’

Island-specific work has been done to boost seabird populations and get ecosystems back in line – on Canna, for example, seabird numbers were revitalised following a successful Trust-led project to eradicate rats from the island. Our experts are watching, working at and maintaining sites on St Kilda, Mingulay, St Abb’s Head, Iona and more every day.

As I stand on the rocks of Hirta, my eyes trace the edge of the escarpment around to the cleft between two land masses where puffins nest, while visitors wander amid the relics of our human history. I spy a National Trust for Scotland ranger discreetly working away. I marvel at how neither visitor, winged or otherwise, is aware of the amount of work that goes into managing and protecting places like this so that we can experience them too. In times gone by, the human residents of St Kilda managed to live in harmony with the wildlife in the most remote of environments. While times have changed, our duty to protect such places and their residents – whether bird or mammal – remains.

‘We have an obligation, in the same way as we have to look after Machu Picchu, the pyramids or the Taj Mahal’, says Susan. When she talks, it’s hard not to hear her voice breaking with emotion. She pauses, and I can hear the clamour of the seabirds ring in my ears, too. ‘I can’t imagine going to St Kilda and it being silent.’

Liza Cole at St Abb’s Head
Property manager at St Abb’s Head, Liza Cole warns of the wider impact of declining seabird numbers

Storms, too, have increased in frequency and severity. ‘In the first half of 2018 we received numerous reports of dead and dying seabirds washed up on the shore following the “beast from the east”,’ adds Richard. ‘Seabirds often die at sea over winter due to food shortage, but this increased level of mortality plays out in the size of their breeding colonies.’ Atlantic puffins, for example, can live for more than 30 years and don’t have large clutches of young. Changes in the type and amount of food available can make their breeding even less successful, the consequences of which we’re only beginning to see.

The patterns witnessed on St Kilda are mirrored elsewhere. Liza Cole is property manager and senior ranger naturalist at the Trust’s St Abb’s Head National Nature Reserve – where breeding pairs of kittiwakes have fallen from over 7,000 in 2005 to just under 5,000 in 2017. ‘All creatures in an ecosystem are interlinked’, she says.

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