The world’s largest northern gannet colony has suffered a 20,000 fall in its population due to bird flu.
A count carried out by researchers in June showed that the gannet population on Bass Rock, an island in the Firth of Forth, has fallen from 75,000 sites to about 55,000, down 25-30 per cent since the last major count in 2014.
A “site” is an area of the colony occupied by a single bird or pair of birds.
The “concerning” and “significant” drop in bird numbers is attributed to a large number of deaths during a bird flu outbreak. Last year more than 90 per cent of breeding on Brass Rock failed due to the outbreak.
Yet scientists remain hopeful of a recovery in numbers after this year’s breeding season showed no evidence of widespread mortality.
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Bird flu was confirmed on Bass Rock in June last year, at the height of the northern gannet’s breeding season.
The researchers used new technologies to determine the impact of bird flu on the colony size, making use of drones and machine learning to better understand the gannet colony in the aftermath of the bird flu outbreak.
“Until the outbreak of avian flu in 2022 the Bass Rock colony had increased relentlessly for more than a hundred years becoming the world’s largest gannet colony in 2014,” said Professor Mike Harris and Professor Sarah Wanless, fellows at the UK Centre for Ecology & Hydrology.
They added: “The development of new technologies couldn’t have come at a better time and will give us the best chance of documenting how the gannets respond to the unprecedented impacts of avian flu.”
Academics conducting research of the colony said they were able to operate the drones and carry out their work without disturbing the gannets.
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Emily Burton, a conservation officer at the Scottish Seabird Centre, said it had been “reassuring” to see evidence that bird numbers were recovering but she remained concerned about the impact of bird flu.
The centre has urged Holyrood to accelerate the production of a Scottish seabird conservation strategy to ensure the protection and restoration of marine habitats.
Scotland is an important habitat, with a third of Europe’s breeding seabirds found there.
Burton warned that “without urgent action, some of our most iconic seabirds could be extinct within 30 years”.
Separately, the Royal Society for the Protection of Birds reported the first rise for five years in the corncrake population in Scotland. Corncrakes are small brown birds which spend winter in Congo but migrate to Scotland to breed.
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The RSPB recorded 870 calling male corncrakes, compared with 828 last year. The charity attributed the rise to its work with communities to increase the quality and quantity of suitable habitats and corncrake-friendly land management practices.
