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21 February, 2020

Seabird declines may be slowing

Seabird declines may be slowing: Guillemots at Fowlsheugh ©Lorne Gill SNH

The decline in Scotland’s breeding seabird numbers may be slowing down, a new report suggests.

The latest biodiversity indicator published by Scottish Natural Heritage (SNH) uses data largely collected by volunteers to look at numbers of 11 species of breeding seabird.

The results show that, having declined by more than 30% from 1986 to 2011, population levels have since remained fairly stable.

Overall numbers have declined by an average of 32% since 1986. Only two of the species have maintained or increased in breeding numbers over the period (common gull and common tern).

Arctic skua, whose breeding stronghold is the Northern Isles, has experienced the largest decline of 78%. Their decline has been linked to changes in the availability of sandeels, which has also affected Northern Isles populations of kittiwakes and terns. Declines are also apparent for herring gull and great-black backed gulls across Scotland.

While below earlier levels, there are signs of some populations such as guillemot and black-legged kittiwake stabilising, with some colonies showing increases. 

Common tern and Arctic tern numbers increased since the last report. Terns are known to be highly variable in breeding numbers and it is too early to say if this trend is going to continue.

Seabirds are not only vulnerable to changes in the seas around Scotland, many migrate across the Atlantic and technology is beginning to improve our understanding of their movements.

Rats and American mink are predators to breeding seabirds and removing these from seabird colonies is a crucial step in securing Scotland’s seabirds for the future. Increases have been recorded at colonies where rats have been removed, such as the Shiants and Canna.

Simon Foster, SNH’s Trends & Indicator Analyst, said: “Seabirds are long-lived, for example the oldest guillemot in Scotland (and the rest of the UK) was recaptured on the Isle of Canna last summer being at least 41 years old. In Wales a razorbill was recorded at 42 years old, while a Manx shearwater has been found more than 50 years old.

“Clearly we need long-term data to really understand what is happening to different species, and the fantastic work by volunteers undertaking monitoring at colonies around Scotland is invaluable in providing us with a unique picture on these changes.”

A UK wide seabird census is also currently underway and the results from this will help to provide an overview on all of the species of seabirds breeding around Scotland. These surveys rely on volunteers and they are always looking for more people to help. If you would like to get involved in seabird monitoring please contact:


Media enquiries: Contact the SNH press office on 0131 316 2655 or

Contact information

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Notes to editors

The full report is available to read here:

Scottish Natural Heritage is Scotland's nature agency. We work to improve our natural environment in Scotland and inspire everyone to care more about it. We work to ensure that all nature in Scotland - our key habitats and landscapes, all our green space and our native species - is maintained, enhanced and brings us benefits. It is the job of all of us to achieve a balance in the sensitive management of our natural world in order to maintain and enhance biodiversity. For more information, visit our website at or follow us on Twitter at

'S e Dualchas Nàdair na h-Alba buidheann nàdair na h-Alba. Tha sinn ag obair airson ar n-àrainneachd nàdarra ann an Alba a thoirt am feabhas agus a h-uile duine a bhrosnachadh gus barrachd cùraim a ghabhail dhi. Gus am bi an nàdar air fad ann an Alba – ar prìomh àrainnean is chruthan-tìre, ar n-àiteachan uaine gu lèir is ar gnèithean dùthchasach - air an gleidheadh, air an leasachadh 's a' toirt bhuannachdan dhuinn. 'S e an dleastanas a th' oirnn uile co-chothrom ann an stiùireadh faiceallach ar saoghail nàdarra a ruighinn airson bith-iomadachd a ghleidheadh 's a leasachadh. Airson an tuilleadh fios, tadhail air an làraich-lìn againn aig no lean air Twitter sinn aig


Guillemots at Fowlsheugh ©Lorne Gill SNH

Guillemots at Fowlsheugh ©Lorne Gill SNH

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