Avian flu ‘Wake-up’ call as fears rise for Scotland's seabirds

This year, however, seabird experts are on edge, wondering how many will arrive and if the coming breeding season will bring a repeat of the thousands of flu-stricken corpses seen last year.  

With the avian influenza pandemic intensifying, there are calls for new measures to conserve Scotland’s threatened species and give them the best chance of surviving.

Paul Walton, RSPB Scotland’s head of habitats and species, said: “We need to use this as a wake-up call and we need to build resilience in our important wildlife populations, in particular our seabird populations, so that when new anthropogenic pressures like this come along they are better able to cope.”

Scotland is of major importance for seabirds because our coasts and islands are home to many key species.

We have 45 per cent of the world’s population of gannets and 60% of the world’s great skuas breeding. Around 40% of Manx shearwaters nest here.  

We also, in recent years, have highly pathogenic avian influenza (HPAI), commonly called bird flu.  

More than 11,000 gannets were recorded dead last summer, but it is believed many more will have died at sea, their corpses never to be found.

In guillemots the mortality count was 3,300 last summer, and in great skua it was 2,200 last year, that’s 7% of the entire global population of this bird. Of those deaths 1,400 on Foula, Shetland.  

To get a perspective on the impact, compare how Covid-19 affected humans, causing 217,000 deaths in the UK, around 0.3% of the country’s population.

Compare that 0.3% with the one-third of Svalbard geese population that were wiped out by bird flu in winter 2021 or the (certainly under-recorded since many birds simply die at sea) 3% of Scotland’s gannets,

At the Scottish Seabird Centre, in North Berwick, which looks out over the water towards the Bass Rock, chief executive Susan Davies said the staff were “all on tenterhooks” over what will happen when the gannets return to their breeding grounds over the coming months.  

She recalled the events of last year. “On the world’s largest colony of Northern gannets – the Bass Rock in the Firth of Forth – there were thousands of dead birds and deserted nests and young,” she said.

“More than 5,000 dead birds were counted, following a whole island drone survey undertaken by the University of Edinburgh, on a single day in a colony that normally has 150,000 birds.

“We know many more birds died before and after that. The scale of impact was heartbreaking to see.”

The worry is disease and death will return with the migratory birds. She added: “Will HPAI take hold again or will some of the birds have built up resistance?”.  

Dead gannets on beach North Berwick, copyright Susan Davies Scottish Seabird Centre 

Avian influenza has long been circulating in wild bird populations, but until recent years it was generally the very mild disease, low pathogenic avian influenza.

It was only in the late 1990s that the new extremely lethal type of HPAI, which is now a pandemic, emerged in China.

The UN Food and Agriculture Organisation concluded it originated in poultry in East Asia and passed to wild birds secondarily, and that the movement of poultry  and poultry products has been a principal vector across Eurasia, alongside migratory movements of wild  birds.

This is a disease, RSPB Scotland’s Paul Walton emphasised, that came out of the global poultry industry.

Research has shown that migrating wild birds have indeed helped to transport the virus. However, it’s not a simple story of wild birds now infecting poultry.  

Some studies in North America and Germany have found the disease has moved back and forth between poultry and captive birds.

It is suggested some wild species, such as owls and kestrels, are picking it up from mice that are coming out of poultry units that have got the virus on their fur.

It was not until two years ago that Europe began to see what Mr Walton describes as “big population-level impacts on wild birds”.

That year whole colonies of Dalmatian pelicans were wiped out in Greece and more than 5,000 European cranes were counted dead in Israel. In the UK, in the summer of 2021, it was also noticed great skuas in the Northern Isles of Scotland were ill and dying.  

When tested, they were found positive for HPAI.  “This,” said Mr Walton, “was a real surprise because this disease had really been most characteristic of wildfowl, birds like ducks and geese. To suddenly have it into seabirds was really very new.”

The following winter the disease was indeed seen in wildfowl populations in Scotland, and the Svalbard barnacle geese, which breeds in Greenland and winters on the Solway Firth, was particularly hit badly.  

Of the population of around 40,000, according to reliable counts, one-third died.

Then, last summer, when the great skuas came back  from their migration to the west of Africa, they were sick again. In the months that followed the disease started appearing in other species, and moved down from the Northern Isles to the east coast of Scotland, right down to the gannet colony on Bass Rock, and beyond.

Seabirds dying en masse of avian influenza was unprecedented. “It has never happened before in recorded history with bird flu,” said Mr Walton.

“And this disease is ultimately anthropogenic. Wild birds can of course move the disease around, but ultimately this originated in poultry systems in Asia. Global farming is the origin of it.”

Unlike geese which, given good habitat and low mortality can breed quite quickly and make up population losses relatively easily, many seabirds, and some other species such as birds of prey, are naturally very long-lived birds with slow breeding rates.

“When adults start dying like this, they often can’t breed fast enough to make up the losses and the population declines.”

The unfolding tragedy, has, he said, been “unbelievably distressing”.

A large programme of seabird monitoring is planned for the coming spring and Nature Scot, formerly known as Scottish Natural Heritage, has an app through which ornithologists can record dead birds, with 2,192 reported across 45 species since October.

Claire Smith, the RSPB’s senior policy officer on avian influenza, has been monitoring the recent deaths, and observed: “There have been barnacle geese, pink-footed geese, gulls, Canada geese. There have been really high numbers of mute swans across the city parks in Glasgow. Raptors have been affected, deaths in peregrines are increasing, big numbers of buzzards.”

There are likely to be carcasses again on our beaches over the coming year and the RSPB is also seeking government guidance on how to handle their removal. Smith said: “A lot of people want us to pick up dead birds and there is logic to trying to reduce the viral load if they’re in water bodies, but there are not clear routes on how to dispose of birds, particularly in rural areas." 

Some species have, so far, escaped the impact of the disease. For instance, Scotland’s iconic puffins appear to have, so far, been relatively little affected by avian flu. One theory is they are burrow-nesters and therefore not so crammed up together in colonies, as gannets are, and so are perhaps less vulnerable to mass spreader events.  

The species also provide an illustration of how not all mass bird deaths are to be written-off as bird flu. Puffins recently found washed up in the Canary Islands are thought to have died of starvation after being blown away from their usual territories by rough weather.#

Puffin eating, by Bryan Walker

There are many questions still to be answered about the disease and RSPB would like to see more research.

But also, Ms Smith observed,there is concern that because dead birds are now only being tested for the disease and not other causes of death – such as poisoning or starvation – a fuller picture of impacts on the birds is being lost.

The truth is that, for seabirds, avian flu is just one of many threats.  Even before the virus arrived at our shores, many populations were already in decline. The national index of breeding seabirds, managed by Nature Scot, which monitors the breeding numbers of 11 species, between 1989 and 2019, before bird flu arrived, had dropped, catastrophically, by almost half.

Some of that drop is believed to be caused by climate-change impacting on food chains that feed the sand eels many of the birds commonly eat. Other key impacts are deaths as fishing industry by-catch and predation by invasive mammals on breeding islands.

RSPB Scotland believes the best  way to help the country’s birds survive this devastating bird flu is to reduce the other pressures on them and the organisation is making a series of calls to government.

Mr Walton said: “A major programme of targeted conservation measures for seabirds will help to build their resilience to these novel pressures, of which this is just the latest one.”

End industrial sand eel fishing in UK and Scottish waters. We know that fishing for sand eels competes with seabirds like kittiwakes. Sand eel fishing reduces kittiwake breeding performance on the east coast of Scotland.  

Create a national programme of island restoration where invasive mammals are eradicated on islands which are important for seabird breeding and following that a legacy of biosecurity to stop new invasions of mammal species on those islands.

Put in place by-catch monitoring on all long-line fishing vessels in Scottish waters – and then work with the fishing industry to find solutions.

Ensure that the development of offshore renewables actually delivers nature-positive gains. Make sure the developments are designed and sited to minimise impacts on birds and that some of their profits are used to fund seabird conservation measures.

Effectively protect and manage our marine protected areas, so they are not just paper parks. We really need no-take zones, no extractions zones. These have been shown world wide to have huge benefits for marine wildlife, including seabirds, and for human fisheries too.