St Kilda: Census finds huge decline in island chain's seabirds

Scotland’s largest conservation charity, the National Trust for Scotland, carried out the count as part of its vital work to help protect Scotland’s National Nature Reserves. 

And just as man once abandoned the four islands which make up St Kilda, it appears as though some species of birds’ time is also drawing short, with more than half their number disappearing in the census recorded by the Trust’s volunteers and rangers.  

St Kilda was abandoned 93 years ago when life became unsustainable for its few remaining human inhabitants, and is today a nature reserve home to small rangers’ station, a resident population of sheep and thousands of sea birds.

The new census by the Trust’s seabird experts identified a 61% decline across four types of cliff nesting seabird: fulmars, guillemots, razorbills and kittiwakes. 

Razorbills on St Kilda 

At one time St Kilda was the only place in the UK which was home to fulmars. The charity’s staff and volunteers were dismayed while carrying out this year’s census as it became clear there were far fewer fulmars than they had hoped to find.

Taking the data from their notebooks, they realised that fulmars have declined by a huge 69% since the last full census of all four islands that make up St Kilda. For every fulmar nest they were counting, there should have been three more.

The declines are even greater for the kittiwake, a small gull with a lemon-yellow beak, that the team found has declined by 84% since 1999.

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Guillemots and razorbills, which huddle together on the cliffs in large numbers during the summer, contributing the droning gargling noises of the seabird colony cacophony, have also declined by over 35%, making the noise just that bit quieter. 

To carry out the census, the team counted from land, hiking to every nook and cranny of the main island in the archipelago, Hirta, and from the sea, using binoculars.

The census took around 1,400 hours to complete during the first three weeks in June. Three members of the Trust team, including St Kilda’s Seabird Ranger Craig Nisbet and Senior Seabird Officer Ellie Owen, were joined by six highly skilled volunteers and other Trust staff.

The last St Kildans left 93 years ago

Seabirds have long been synonymous with St Kilda, even impacting the unusual buildings which were created to store produce and fowling equipment.

Before the evacuation of the final 36 St Kildans on 29 August 1930, thousands of people lived on the island – farming, fishing, and, most importantly, harvesting seabirds and their eggs.

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Susan Bain, Western Isles Manager at the National Trust for Scotland, said: “The decline in seabirds on St Kilda is not only concerning from a natural heritage viewpoint but also from a cultural heritage viewpoint.

"The exploitation of seabirds was integral to the community that lived on St Kilda, it is what allowed them to settle and live on such a small island for thousands of years.

“They ate the meat and eggs, used the oil for light and ointment and traded the feathers. Many of the few songs that have survived tell of fowling expeditions and the dangers associated with it.

“The decline in seabirds diminishes the World Heritage Site and is a clear signal that our marine ecosystem is under immense pressure.”

Ellie Owen, Senior Seabird Officer at the National Trust for Scotland, added: “The census took a lot of time and resource to complete but it’s incredibly important that we capture this data to identify how wildlife is faring across the places our charity cares for.  

“It’s only by identifying the declines and trends in our seabirds that we can begin to consider how to help them.   

“We don’t have a full picture of what has led to the decline on St Kilda, but climate change has certainly played a part, affecting elements such as the food supply in the surrounding sea."

She added: “Declines in natural prey such as sandeels are likely also impacting them, and closing Scotland’s waters to the foreign-based sandeel fishery would be a powerful step to helping our seabirds.  

“We also need to work with government and fisheries to reduce the accidental bycatch of fulmars on longlines, using available mitigation measures.”