Deadly avian flu ravaging Scotland's wild birds began in the poultry factory farms that could be source of next big human pandemic – Philip Lymbery

Covered head to toe in hazmat suits, gloves and facemasks, sombre figures comb clifftops and tidelines searching for corpses.

The close confinement of chickens can create the perfect breeding ground for new types of diseases to emerge (Picture: Jamie McDonald/Getty Images)

It’s an all-too familiar scene, particularly in these pandemic times. Yet, this was no twist of Covid. Instead, it was the devastating impact of a new disease ravaging wildlife: highly pathogenic avian influenza (HPAI).

Rangers usually seen counting colonies swirling with seabirds were instead painstakingly collecting carcases of dead birds before bagging them up for incineration. It’s a devastating task going on across the islands and coastlines of Scotland and elsewhere in a battle to prevent more carnage from further infections.

NatureScot, the public body responsible for Scotland’s natural heritage, is “extremely concerned” about the impact of the current H5N1 strain of avian flu on internationally important seabird populations.

The fear is that long-lived and slow-breeding seabirds like gannets and great skuas could see their numbers plummet and take decades to recover. Even greater are concerns that the disease could get into really rare species like red-necked phalaropes, dainty little shorebirds with a tenuous foothold at best.

The first signs of HPAI in Scottish seabirds were detected toward the end of the 2021 breeding season. Great skua colonies were found to be affected in Shetland, Orkney and St Kilda. The disease was then found in gannets at the national nature reserves of Noss and Hermaness.

Many seabird species have now tested positive for HPAI. By mid-July 2022, infected birds had been found at more than 140 sites across Scotland involving 28 different species.

A perfect breeding ground for disease

It’s a tough lesson in how our food choices affect everything else. HPAI, which now regularly devastates poultry populations around the world, didn’t originate in wild birds.

Instead, it emerged in farmed birds during the massive expansion of the poultry industry in China and east Asia at the end of the 20th century.

Now, chickens and wild birds alike have become victims of this most devastating disease.

The rise in intensive chicken farming has provided the perfect breeding ground for new and more deadly strains of disease. The explosive growth of cheap chicken on supermarket shelves is now coming home to roost.

Evolution of the virus

The low pathogenic version of the avian influenza virus is common in birds, both domesticated and wild.

Its evolution into a much more deadly form is due to the huge numbers of birds kept at close quarters in the global poultry industry.

The science behind the emergence of dangerous disease strains isn’t complicated.

These days, most chickens are crammed in their tens of thousands in each steely-looking barn. A ‘farm’ can now have any number of these long, low buildings lined up in rows.

Keeping too many animals in too small a space, often in dark, filthy and overcrowded conditions, provides the conditions a virus like avian influenza needs to spread and evolve.

As the virus races through the flock, new – and potentially more deadly – strains can and do emerge.

Rampant across Europe and Asia

Contrary to what some in the farming industry want us to believe, keeping farmed animals indoors increases the risk of disease.

With the highly pathogenic bird flu virus now rampant across Britain, Europe and Asia, farms of all shapes and sizes are being hit.

According to the European Food Safety Authority (EFSA), by far the most common reason for the disease spread in poultry is through farm-to-farm transmission. In other words, it’s being carried on the trucks and boots of the industry.

The shocking reality is that HPAI in Britain and Europe could become endemic in wild birds, causing immense damage to wildlife already fighting for survival.

As it is, farmland bird species have plummeted in recent decades due to the rise of intensive agriculture. Skylarks, corn buntings and lapwings are among the species particularly affected.

Spreading to wild mammals

Now, that same farm intensification is devastating a wider range of wildlife previously thought out of harm’s reach, such as seabirds on remote islands.

According to NatureScot, great skua, gannet and guillemot have been hardest hit. Surveys suggest Shetland’s gannet numbers have dropped by a quarter. Great Skuas in Orkney have seen declines of up to 85 per cent.

There is worrying evidence that HPAI is starting to spread into wild mammals such as foxes and seals. All of which underscores how we’ve created a world out of balance and increasingly out of control.

As a lifelong conservationist, I’ve long believed in the importance of nature reserves in giving nature a home. And I still do.

Yet, this latest tragedy, now playing out across some of the remotest and wildest of locations, shows nothing is safe anymore. Even the best protected wildlife is vulnerable. It’s a big lesson in how everything is connected; that the well-being of society and the ecosystem we depend on is interlinked with the health of farmed animals.

Pandemic risk

Thankfully, HPAI rarely affects people, at least for now. Official government advice is that avian influenza is “primarily a disease of birds and the risk to the general public’s health is very low.”

The bird flu virus is not easily transmitted between people, but scientists have suggested that just a few mutations would allow it to become as infectious as seasonal flu.

An editorial in New Scientist magazine described the risk of a pandemic as “fact, not fiction”.

What is becoming clear is that the intensive poultry industry’s damage to wild birds and potentially other wildlife is growing year by year.

Cheap chicken on supermarket shelves looks set to become one of the most important global threats to biodiversity, and a possible pandemic threat to people too.

Philip Lymbery is global CEO of Compassion in World Farming, a former United Nations Food Systems Champion and author of Farmageddon: The True Cost of Cheap Meat and Dead Zone: Where the Wild Things Were. His new book Sixty Harvests Left: How to Reach a Nature-Friendly Future is out now. He is on Twitter @philip_ciwf