Avian flu crisis leaves seabird populations on the cliff edge

Scotland has been experiencing an avian flu crisis, with around 20,500 seabirds reported dead around the country’s coastline this summer  – but a NatureScot taskforce is taking urgent measures to minimise the risk to other wild birds

AS we head into the winter, vigilance remains high over the avian flu outbreak that has had a devastating impact on Scotland’s wild bird populations in the past 12 months.
The scale of that impact has become ever clearer in recent weeks.

Figures from NatureScot show that around 20,500 dead seabirds across around 160 locations were reported between April 4 and September 11 this year. That is on top of an estimated 13,200 Svalbard barnacle geese that had died by the end of winter 2021/22.

In the face of this biodiversity crisis, a Scottish task force led by NatureScot is working flat out to gain a better understanding of the virus and take the necessary action on the ground to protect wild birds.

Eileen Stuart, NatureScot’s Deputy Director of Nature and Climate Change, said: “Avian influenza is a virus that mainly affects birds, with migratory species, especially water birds, carrying different strains along their migration routes to a greater or lesser extent every year.


“Previously, levels of avian flu have remained quite low but this year, for some reason, the virus has been particularly virulent in the wild bird population with devastating consequences. 

“Sadly, it is our seabird colonies that have been hit the hardest because of the way the virus is transferred though feathers and faeces, spreading quickly in populations that congregate together in close proximity.

“The most badly affected species recorded were northern gannets, great skuas and guillemot. However, the figures we have recorded will be a significant underestimate as many birds will have died at sea. The ecology of these species, including slow reproductive rates and delayed age at first breeding, means that recovery of these populations is likely to be slow.

“And on top of this our seabird populations are already at risk from a number of factors – the climate crisis has affected certain species of fish, that they feed on; and plastic pollution in the oceans is of grave concern.

“All of this is not just a Scottish issue. Scotland is home to high percentages of the world’s population of some of these birds – 60 per cent of the world’s great skuas live here, for example, and 40 per cent of gannets – so this is an international crisis, that requires an international response.”

Avian flu has caused big impacts at seabird colonies elsewhere, especially tern colonies in England and continental Europe, at great skua and gannet colonies in Faroe and at gannet colonies across the Atlantic in Canada.

The current situation in Scotland follows a large outbreak in Svalbard barnacle geese here in 2021, where the particular strain H5N1 is estimated to have killed between 30 and 40 per cent of the wintering population. 


Barnacle geese at Caerlaverock National Nature Reserve


In spring 2022, significant die-offs were noted in eider flocks, and over the summer there were thousands of dead great skua and gannet reported at breeding colonies, and hundreds of other seabirds reported dead, particularly guillemot, with smaller numbers of terns, gulls and other auks.

At some seabird colonies, for example Bass Rock, which was the world’s largest gannetry, large parts of the colony were impacted. For some great skua colonies, known casualties are almost half the number of expected breeding adults. Avian flu has also been found across species, with reports indicating pink-footed geese, buzzards, mute swans, a red kite and sea eagles have been affected. 

“Tragically, this disease could be with us for some time to come, which is why NatureScot is working so hard to bring all of the key players together to make our bird populations – and our biodiversity – more robust,” Ms Stuart added.

In response to the crisis, NatureScot set up a task force in the summer to co-ordinate a national response, and also established a sub group of its Scientific Advisory Committee, bringing together scientists across a range of specialised fields to provide further support on surveillance, monitoring and related research to allow better understanding of the current and likely future impact of the disease on wild bird populations. 

“The aim was to bring together all the key players to, firstly, communicate to the public the issues surrounding avian flu – for example, the risk to human health which is, thankfully, very low – and to prepare and publish practical guidance and information; and, secondly, to co-ordinate and monitor wild bird populations, working with scientists across the UK to understand how the virus is transmitted and how its impact on wild birds can be limited,” said Ms Stuart.

“It is a huge challenge – there is very little we can do to stop the spread of avian flu in wild bird populations, so we need to work with others and look at measures we can take to minimise other risks to wild birds, such as tackling invasive species that prey on wild birds. While NatureScot’s remit only extends to wild birds, it’s clear there has to be an integrated approach that also tackles the spread of avian flu in domestic birds and poultry.”

Following an increase in the number of detections of avian flu in wild birds and other captive birds, the Chief Veterinary Officers from England, Scotland and Wales have declared an Avian Influenza Prevention Zone (AIPZ) across Great Britain to mitigate the risk of the disease spreading amongst poultry and other captive birds. 
This means that it is a legal requirement for all bird keepers in Great Britain to follow strict biosecurity measures to help protect their flocks.

“Adhering to and maintaining the highest biosecurity must remain at the foremost of people’s minds whether working with domestic or wild birds,” explained Ms Stuart.

“At the moment we are receiving reports of localised outbreaks in geese, swans and gulls, most notably in the Moray area and at Hogganfield Loch in Glasgow. However so far, thankfully, this is nowhere near the extent of last winter at the same stage

“There is very little risk to human health, but people should continue to avoid touching sick or dead wild birds and keep dogs on the lead in areas where there are infected birds.”


Surveillance results will shape future recovery plans

NOW that the seabird breeding season is over and colonies have dispersed, concerns remain about how the avian flu outbreak could evolve over the winter and affect migrating goose populations and other waterfowl and waders.

NatureScot has set up a surveillance network to monitor wild birds this winter.
Real-time information gathered by a team of site managers and volunteers across the country is feeding into the work of the avian flu task force, helping it to provide swift advice to government, conservationists and land managers on practical actions to help reduce the transmission and impact of the virus.


Eileen Stuart, NatureScot’s Deputy Director of Nature and Climate Change, said: “We are working with colleagues in Iceland and Norway to identify cases in migrating populations, and early counts of barnacle geese are currently taking place at key sites on the west and north coast to help guide management decisions.

“The task force is also overseeing the development and implementation of the upcoming Scottish Avian Influenza Response Plan.”

The NatureScot Scientific Sub Group, established earlier this year, is considering the extent to which different activities may disturb birds, leading to increased infection and slower recovery rates, and will update their advice in light of the latest evidence.

Looking ahead, Ms Stuart added: “It is too early to say what the long-term population impacts might be. There is still a huge amount to learn about the virus – its persistence in the environment and whether birds can develop resilience to the virus will be key factors determining long-term population impacts.  

“All seabirds are relatively long lived, take years to reach reproductive age and invest heavily in a single brood each year. This means that significant impacts on the adult population, in combination with other pressures, can result in a slow population recovery.”

Experts are unsure as to why avian flu has become more virulent this year, or why it has affected great skua, gannet, barnacle geese (and terns elsewhere) more than other species. 

“Avian flu is the latest and most devastating indication of how biodiversity loss makes our wildlife increasingly vulnerable,” added Ms Stuart.

“As we look ahead to the biodiversity COP15 in Montreal this December, protecting and restoring our biodiversity will have a key role to play in our response and resilience to viruses such as avian flu.”

The situation is “very emotional”, she added.

“It’s very sad, and even if the risk to human health is low, it is still very distressing to see dead birds on beaches, for example,” said Ms Stuart.

“The response from the public has been heartening – people value our wildlife and it has been encouraging to see that.

“And there are things people can do to help, through getting involved in some of the monitoring work, for example, or volunteering with the RSPB.”

She added: “It is only by joining all of these things together with the work being done by NatureScot and other organisations, that we can create an overall recovery plan.”


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