Hundreds of thousands of wild birds have been affected by the new H5N1 flu strain, particularly seabirds that live in densely packed colonies. Photo / Phil Botha, Unsplash
Hundreds of thousands of wild birds have been affected by the new H5N1 flu strain, particularly seabirds that live in densely packed colonies. Photo / Phil Botha, Unsplash
The sound of a seabird colony is overwhelming. The air is thick with kittiwakes, guillemots, razorbills and shags. Shrieks and calls ricochet down the cliffs and the rhythmic flap-flap of wings cuts the air like stadium applause. Birds ride the wind in spirals, dive to the waves, burrow into shelvesin the cliff face or settle on rocky promontories.
The summer breeding season is coming to an end for many of the species at St Abb's Head nature reserve in Scotland's East Lothian, 80 kilometres east of Edinburgh. Adult guillemots and their chicks have already migrated to their wintering grounds. I'm sitting on a grassy verge at the cliff's edge, overlooking the rocky bay that houses the colony, with Ciaran Hatsell, a National Trust of Scotland ranger. "I get empty nest syndrome at the end of the season," Hatsell says, half smiling. "It's like 60,000 of your kids leaving all at once."
Hatsell knows about loss. On June 5, he discovered the first signs of avian influenza in one of the gannets. Since then it has wiped out thousands of birds on the reserve. The flu is a highly pathogenic strain of the H5N1 virus. Since its early detections in poultry and wild birds in the spring of 2021, this new strain has killed more than 86 million birds in the US and Europe alone, predominantly through poultry culling, the mass slaughter of birds at sites where cases have been found. The European Food Safety Authority said the 2021-2022 epidemic season was the largest ever recorded on the continent.
Hundreds of thousands of wild birds have been affected too, particularly seabirds that live in densely packed colonies — optimal conditions for the spread of disease. The level of transmission in wild bird species is unprecedented. Whereas previous strains have affected a handful of species before petering out by the end of the winter, the current one has infected hundreds of species and hung around in populations year-round.
In Rajasthan, India, locals looked on in alarm in November last year as Demoiselles cranes, elegant grey-blue birds with long black necks, began showing signs of lethargy and confusion. Three hundred of the three-foot-tall birds, which feature prominently in Indian poetry and mythology, are said to have died. The virus spread west, wiping out 8000 common cranes in Israel, "the worst blow to wildlife in the country's history", according to the environment minister. At Greece's Lake Mikri Prespa, home to the world's largest Dalmatian pelican colony, more than half of the enormous, prehistoric-looking birds perished. An annual census of the species across the Balkans in May revealed a 40 per cent decline in the population compared to last year.
At Greece's Lake Mikri Prespa, home to the world's largest Dalmatian pelican colony, more than half of the enormous, prehistoric-looking birds perished. Photo / Sebastian Pandelache, Unsplash
In Scotland, among the worst-hit countries because of the concentration of seabirds on its coasts, the virus has wiped out more than half of the great skua colonies in Orkney and St Kilda. Scotland is home to about 60 per cent of the world's great skuas, a predatory bird known as the pirate of the seas. Conservationists warn that the scale of mortality could push the species into local extinction.
In a pre-Covid-19 world, all this might have been a major global news story. But with the pandemic, Russia's invasion of Ukraine, a looming recession and another infectious disease that presents a greater risk to humans — monkeypox — dominating headlines, avian flu has barely made the agenda.
"I've worked in conservation for 30 years and I've never seen anything like this," says Susan Davies, chief executive of the Scottish Seabird Centre in North Berwick. The centre has for years organised trips to the Bass Rock, home to the world's largest gannet colony, now site of one of the most significant H5N1 outbreaks. Drone images comparing the Bass Rock this June with September 2020 reveal the extent of the devastation. The rock, usually gleaming white with gannets, is muddy brown, with large empty patches.
At St Abb's, the virus spread through the colony at relentless speed. Of the 109 gannet nests Hatsell counted this breeding season, only one chick has survived. "This is a population level event, and it's happening in our lifetimes," he says as we walk along the cliff. "Species that we've been working [to conserve] are potentially going to be wiped out."
It's not just gannets. From where Hatsell and I are perched, we can see a group of dead kittiwakes lying on an outcrop below the lighthouse, near a roosting spot that Hatsell believes was a key point of transmission. The area around the bodies is empty, as though the other birds know to stay away.
Rangers like Hatsell have been the first and, often, the only responders in this outbreak. He and his colleagues at ecological sites around the UK, including his partner, who works on the Farne Islands off the coast of Northumberland, just over the border, have been donning PPE and clearing the infected carcasses in an attempt to contain the spread. "The jobs that they loved . . . have turned into a dystopian dream," Hatsell says of his colleagues. "They are in full hazmat suits and respirator masks, putting birds in bin bags. It's like something out of a film."
There have only been two recorded cases of the new H5N1 strain in humans, but 456 people have died since 2003 after catching previous strains of the virus, according to the World Health Organisation. Emerging infectious diseases are a growing threat to both humans and animals, as virologists have warned for decades, to little effect until Covid struck.
Since its early detections in 2021, this new strain has killed more than 86 million birds in the US and Europe alone, predominantly through poultry culling. Photo / Egor Myznik, Unsplash
The WHO reports that 75 per cent of new infectious diseases detected in the past three decades originated in animals. With mass urbanisation, industrial farming and the destruction of natural habitats, we are living in closer proximity to livestock, increasing the risk of mutations and spillover into other species. Meanwhile, a study published in Nature this month found that over half of the known human pathogenic diseases have been aggravated by climate change.
Hatsell hands me his binoculars so I can scan the cliff face for chicks. He explains how guillemots begin their migration before they have even learnt to fly. With their parents' encouragement, they leave the nest for the first and last time with a leap from the high ledges down into the water, some as young as 15 days old. Many chicks don't make it, dashed against the rocks. Nature is cruel, but the scale of the mortality rates among wild birds here and around the world seems far from natural.
Outbreaks of disease in domestic birds have been recorded since the late 1800s, with the term "fowl plague" in use until the mid-20th century, and local cullings taking place from time to time. But the H5N1 virus was a game-changer, becoming the first avian flu to cross the species barrier to humans. First detected in a farmed goose in southern China in 1996, the virus was then discovered in poultry facilities across China and Hong Kong. In 1997, 18 people in Hong Kong were found to be infected and one-third of them died. In a desperate move to contain the outbreak, the Hong Kong government killed all poultry in the territory within three days. This was later hailed as helping avert a possible pandemic.
The virus re-emerged in Asia in 2003, and from 2005 was spread by wild birds to poultry in Africa, the Middle East and Europe, including Britain, causing periodic outbreaks. From there it has moved back and forth between domestic and wild birds, evolving as it goes. Seabirds are long-lived and loyal creatures. Some live up to 50 years and don't start breeding until the age of five or six, meaning their birth rates are relatively low. Provided they breed successfully, most remain with their partner for life. "They have the kind of biology that doesn't cope well with extraordinary additional mortality," says Ruth Cromie, scientific lead of the UN-led Task Force on Avian Influenza and Wild Birds. It can take decades to build up a population after mass deaths.
The task force, convened by FAO, the UN's food and agriculture agency, and CMS, its secretariat on migratory species, was launched in 2005, in large part to prevent counterproductive responses like attempts to kill wild birds, as well as misinformation about the role of wild birds in spreading the virus. Ducks and geese were increasingly being demonised in the media. In October 2005, The Sun newspaper ran the headline "Ducks of death" across a photomontage of a flock flying over London. The coverage made Cromie and her colleagues fear for wild bird conservation efforts almost more than the virus itself. "It's like what Jaws did for shark conservation," she says.
Bass Rock, home to the world's largest gannet colony. Photo / Paul Levesley, Unsplash
Marco Barbieri, scientific adviser at CMS, notes that the initial H5N1 outbreak gained global attention because it could infect humans. The current mutation of the virus does not have the same "zoonotic potential" he says, meaning the ability to jump from animals to humans. While there have been two cases in humans, that is low for an outbreak of this magnitude. This might explain the slower response by governments to the outbreaks in wild bird colonies. The Royal Society for the Protection of Birds has criticised the government for being "asleep at the wheel" during the recent emergency. It called for an immediate response plan in England, where tern colonies in Northumberland have been ravaged, and a plan for further possible outbreaks this winter.
A spokesperson for the Department for Environment, Food and Rural Affairs (Defra) told the FT it was developing an English seabird conservation strategy to be published in spring 2023, to assess the vulnerability of each species and propose actions to address them. But Cromie says that most government agencies have given little focus to wild birds in their response planning. "There's always the sense that it's wildlife, so we can't do anything."
It's true that there is little that can be done to slow outbreaks in wild animals once they are infected. "Flu is endemic in wild birds, and we can't vaccinate them or track them with any great detail," says Paul Digard, chair of virology at the Roslin Institute, Edinburgh University's animal science research centre. What can be done, however, is to improve biosecurity in commercial facilities to prevent the virus leaking in or out, and to limit human access to wild bird colonies that have been impacted by the virus, in case we unwittingly spread it to new environments. Governments, meanwhile, could ensure they are better prepared for future outbreaks by installing monitoring and reporting systems to understand the transmission of the virus in wild birds.
Poultry farming in spotlight
Many scientists believe that industrial poultry farming is the cause of the current, highly pathogenic strain. However, because of the difficulty of tracing the spread of the virus in wild birds, this is hard to prove. Digard says that while previous strains originated in chicken farms and can spread to wild species, there is as yet no evidence that this is the cause of the latest outbreak.
Barbieri and Cromie say one way to mitigate the long-term population losses of avian flu is by reducing the environmental pressures seabirds are already under and maintaining populations through conservation. "We need to recognise that all our healths are interconnected," says Cromie. "It's not as if nature is something over there."
"Do you know how many gannets Ciaran has left?" asks Maggie Sheddan, as we speed out of the fishing port of Dunbar on a boat towards the Bass Rock. We skirt along the low, rugged coastline, past Tyninghame beach and the forests devastated by Storm Arwen last year. I tell her what Hatsell told me the day before: just the one chick. "Well, that's something." Sheddan squints, her pale blue eyes fixed on the horizon.
I follow her gaze. The sun has just hit the rock, which rises 350ft out of the sea, its steep cliffs shining. The wind has agitated the birds into orbit. They float in a halo of gold high above the island. Sheddan is smiling wide at the sight, gesturing with her hands as we draw in closer, and the magnitude of the colony becomes apparent. She has been leading landing tours on the island for 20 years. "You'd be forgiven for thinking there was nothing wrong here," she says, laughing up at the sky, which teems with life.
The boat draws nearer and I get a better look at the gannets. With a wingspan of two metres, they are the largest seabirds in the Northern Atlantic. Their plumage is white with black-tipped wings, yellow heads and piercing blue eyes.
During a normal breeding season the rock is blanketed in birds, almost every inch of its surface occupied. But now the population looks drastically thinner, even from a distance, and large areas of rock are empty, with birds lying dead on the lower promontories. We see a chick, recognisable from its fluffier plumage, lifeless in the water.
When a visitor first spotted dead birds on the cameras at the North Berwick Seabird Centre at the start of June, Sheddan headed straight out to investigate. After her boat landed at the rock, she walked up the path and through the gate, as she has countless times, and was immediately met by a couple of gannets dying at the gateway. By the time she reached the main colony, she realised the extent of the devastation. "I was out late in May and it was absolutely fine," she says, shaking her head. "The speed and ferocity of this when it hit was just unprecedented. It was just wiping them out."
'You just want death to come for them'
The symptoms are distressing to see. Lethargy, confusion, birds unable to lift their head and wings, shaking and nodding their head and, when in water, swimming in circles. Sheddan shows me a video of a bird in the final throes of the disease, convulsing and fitting. She says it takes between 24 to 72 hours for the bird to die once infected. "This fitting is horrendous to watch because this is a strong bird who has amazing control . . . " She trails off. "And how long it takes . . . You just want death to come for them."
We pull closer and watch the birds dive down to the cliff at intervals to reunite with their partners. They greet one another by bill fencing: stretching their necks high and tapping their bills back and forth, like a high-frequency double-cheek kiss. Sheddan says it strengthens the bond between partners. Each time she spots a pair reuniting she laughs with joy, pointing out that a pair means a new nest. "That's life, that's hope for the future."
"I can't imagine going out to Bass Rock right now. It had to have been heartbreaking," says Bryan Richards, emerging disease co-ordinator at the US Geological Survey National Wildlife Health Center. He talks to me via video link from his office in Wisconsin. A model duck and an impressive-looking pair of binoculars sit on a cabinet behind him.
"Over the last couple of years, the impacts on wild birds in Europe and Asia have been escalating, both geographically in the number of species, and the scale of individual morbidity and mortality," he tells me. During the last outbreak of high pathogenic avian flu in North America that began in 2014, approximately 100 infections were documented in 20 species of wild bird. During the 2021-22 outbreak, 96 species, and approximately 2500 wild birds have been confirmed to have contracted it in the US and Canada. "Obviously those are a small proportion of true mortality," he says.
As with everyone with whom I have discussed the virus, one of Richards' chief concerns is the scale of mortality and the longer-term effect on bird populations. He tells me about a few island colonies on Lake Michigan that are home to Caspian terns. On Gravel Island National Wildlife Refuge, there were 391 active Caspian tern nests in early June this year. Two weeks later, only one active nest remained.
Cases detected in mammals
Virologists spend a lot of time trying to predict which zoonotic disease will become the next pandemic in humans, but there seems to be far less concern about the spread across wild species. The new strain of H5N1 has not only affected wild birds. In the spring, Richard's colleagues began to detect cases in scavenging mammals. It has since been confirmed in striped skunks, virginia possums, raccoons, bobcat, mink, coyote and, in Maine, seals. "This is a function of our changing globe," Richards says. "We continue to put stresses on remaining habitats, remaining wildlife species and we crowd in all our pathogens together in the same time and space, more frequently than we ever have before."
Human activity poses all kinds of threats to seabirds, as it does to many species. A 2018 study by the University of Aberdeen showed the global population of seabirds had declined 70 per cent since the 1950s as a result of environmental pressures like industrial fishing, pollution, predation by invasive species and climate change. As the sea has warmed and industrial fishing has proliferated, stocks of seabird prey such as sand eels have dropped dramatically, leaving the birds with less food. Seabirds routinely die caught in fishing nets or from ingesting plastic, while heatwaves and extreme weather events mean they are producing fewer chicks.
At the Seabird Centre in North Berwick, a low stone building with a copper roof curved like the tail of a bird, Maggie Sheddan shows me the screens carrying live footage of the gannets from cameras placed on the Bass Rock. I watch a gannet who appears to be showing symptoms of avian flu. The bird seems confused, but is not yet showing signs of lethargy and fitting that occur in the later stages of infection. Just behind it lies a dead bird.
