Why avian flu could drive our rarest wildlife to EXTINCTION
Thousands of seabird carcasses are washing up on Scots beaches – and baffled scientists fear they are powerless to halt the carnage...
BEYOND the cliff-clinging villages of the Banffshire coast, a well-worn track leads up to the precipitous rocky bluff known as Troup Head. This nature reserve is normally alive with a cacophony of breeding birds, who circle their steepling nests in search of the plentiful fish in the cobalt waters far below.
This wildlife haven is home to puffins, kittiwakes and skuas – as well as Scotland’s only mainland gannet colony, a raucous collective of more than 3,000 breeding pairs which draws birdwatchers from far and wide to observe their colourful courtship rituals.
Recently, however, the birds have been vanishing from here in droves. Where once crowded clifftops normally echo to the bill and coo of loved-up couples and the squawk of their hungry chicks, there are empty nests and bare rock. More worrying still, this sudden calamity extends far beyond the gannets of Troup Head.
For months, the dark shadow of sickness has silently picked its way through internationally significant nesting sites the length and breadth of the country.
The culprit is highly pathogenic avian influenza H5N1 (HPAI), an extremely mutable and deadly new form of bird flu, which is ravaging wild birds at an alarming rate. Few species seem immune. Puffins, Arctic skuas, Arctic terns, cormorants and guillemots have all fallen prey to the same disease. Great black-backed gull, herring gull, kittiwake, Sandwich tern and razorbill have also all tested positive.
So concerned are conservationists by the transmissibility of this new strain, visitors have been banned from 23 Scottish islands in a bid to halt the spread of the disease. Public landings from the sea have been cancelled until the seabird chicks have fledged to give them the best chance of survival.
But, for many birds, the action has come too late. The usual throng of ‘twitchers’ at these hotspots has been replaced by carcass recovery teams in white hazmat suits. And the problem is far from confined to Scotland – the Farne Islands off the Northumberland coast were closed to the public last week after large numbers of puffins were found dead.
Eileen Stuart, deputy director of nature and climate change at Scottish Government agency NatureScot, which is coordinating the ban, said: ‘Restricting visits to these islands is not an easy decision, but we are concerned about the devastating impact avian flu is having on our seabird colonies.’
Given the virulence of the disease, a new taskforce – backed by £1.5million from the UK Government – is racing against time to prevent HPAI not only decimating our wild bird populations but also running riot through the Scottish poultry industry, where it has already caused an estimated £25million of damage.
All of which rather begs the question: how much worse will things become before it gets better?
‘These population level impacts in wild bird species are absolutely unprecedented,’ said Kirsty Nutt, of RSPB Scotland. ‘But we won’t know how bad it is for a lot of our seabirds until next spring when we can count them when they return.
‘There’s a chance that the numbers we are seeing might not be quite as horrifying as they appear. Equally, we might get confirmation that they are as bad as we feared. At the moment, chick survival is looking pretty bad in places.’
Gannet numbers on Shetland’s small islands have plummeted by a quarter and at Troup Head, recent counts estimate around 83 per cent of gannet chicks have been lost. In the east, aerial photographs of Bass Rock and Craigleith in the Firth of Forth – normally tightly packed at this time of year with more than 150,000 pairs of breeding gannets – show growing patches of both islands are increasingly sparsely populated.
In the Northern Isles, sample surveys of great skua colonies show an 85 per cent decline in the birds, also known as bonxies, at Rousay in Orkney, with similar mortality rates in Shetland, Fair Isle, the Western Isles, Handa, the Flannan Isles and St Kilda.
Scotland is home to 56 per cent of the global population of breeding bonxies and the decline has sparked fears bird flu could leave the species at risk of extinction.
Although bird flu has been around for years, Miss Nutt said a red warning flag went up last autumn when thousands of barnacle geese were found dead on the Solway estuary in Dumfriesshire.
‘If we see that again in the same birds or different populations this
‘It has had devastating impact on colonies’
autumn this could be a growing issue all year. It’s hard not to start catastrophising, but this could be something that isn’t going away for a really long time,’ she said.
If this new, more lethal strain, persists year-round, it could spell disaster for great skuas, whose breeding population was only 16,000 birds before avian influenza. ‘They are of biggest concern simply because they had a small population size and a limited range before this,’ said Miss Nutt.
But wild bird numbers were suffering declines before bird flu due to food shortages, caused both by climate change and commercial fishing. ‘Thousands of seabirds are killed each year in Scottish waters, caught in fishing nets and accidentally drowned,’ she said. ‘Seabirds are also impacted by invasive nonnative species, by plastic waste, and they can be killed or have access to feeding grounds restricted by unsuitably placed offshore wind developments. And then you are putting avian influenza on top of that.’
She added: ‘It is upsetting, but I think we need to use it to galvanise action rather than feeling doom.’
That sense of urgency is shared by experts involved in the new Avian Influenza Consortium, a group of eight of the UK’s top scientific organisations, which is hoping to plug the gaps in our knowledge of this fast-changing virus. So, how worried should we be?
‘From a human health perspective, not terribly,’ said consortium member Professor Paul Digard, a virologist from the University of Edinburgh’s Roslin Institute. ‘But from the ecological perspective, it’s terrible. It’s not something we’ve seen before in the UK as far as I’m aware. Up until now, HPAI has been a rare sporadic thing, general winter incursions from continental Europe that then go away over the summer. But this one isn’t going away.’
He added: ‘From a virology perspective, I would hope the problem will become less extreme in the wild birds washing up dead on the shores in the next few seasons because the survivors will have some immunity, but that’s an optimistic guess.’
Figures from the Department for Environment, Food & Rural Affairs (Defra) state there are 537 official cases of bird flu among 28 species in 142 locations, but Professor Digard said a huge amount of
Death on the Rock... pictures lay bare disease’s deadly toll
research was still needed. ‘We don’t know why the virus has changed behaviour, we don’t know what species it’s in, we don’t know where it’s going to go. For many species, it is unknown territory for us in tracking bird flu,’ he said.
Where it came from is easier to chart. It was first sighted in poultry in Hong Kong in 1997, following a small outbreak of deadly H5N1 flu in people. ‘It grabbed headlines around the world, because it got from wild birds into poultry and from poultry into people and it killed a third of the people it infected,’ said Professor Digard. ‘It rang huge alarm bells, because at the time, we didn’t know if it would be the start of another pandemic.
‘It turned out not to be able to spread from people to people, so it didn’t go pandemic and it was cleared out of the poultry in Hong Kong by culling. The problem is you can’t clear it from the wild bird population where it had cropped up and it got back into poultry six years later.’
From there, it spread round most of the world through migrating ducks and geese, who appeared to be unaffected by it. Not so other species of wild birds. This summer, its latest mutation has proved deadlier than ever. ‘That’s one of the key questions that this research consortium hopes to answer. Why is it behaving like this now?’ said the professor.
Another is how to prevent the virus invading commercial poultry farms. He added: ‘Commercial poultry is protected by biosafety not by vaccination in this country and the biosafety generally works pretty well. But if the virus becomes endemic and just hangs around all year in our wild bird populations then we are going to have to up our biosafety game, or maybe think about vaccination.’
There are already signs that even the toughest biosecurity may be too weak to fight off HPAI, after the National Farmers Union Scotland (NFUS) highlighted two serious breaches this year. ‘Both were near the coast, one in the north of Scotland and one in the south, close to the Solway Firth, where bird flu left thousands of barnacle geese dead last year,’ said Robert Thompson, chair of the NFUS’s poultry working group.
‘Both had excellent biosecurity in place – we haven’t got a clue how [bird flu] managed to get in. But as I have said for many years, this disease knows no boundaries. I have been in the poultry business for 40 years and I’ve never seen anything like this.’
He said there had been 20 serious outbreaks of bird flu in Scotland in the past six years. ‘If you have an outbreak, the whole flock must go.
With the value of the birds lost and the consequential losses, the cleaning bill, vets’ fees and so on, I would say the bill for the last six years has probably been between £20million to £25million.
‘We bang on about biosecurity every year, but this year it is going to be crucial. We need to get the message out that all people with poultry follow the Government guidelines and keep their biosecurity at the highest possible level, whether you’ve got two hens or 200,000 hens.
‘Most of the smaller units have little or no biosecurity; one incident was at a rescue centre where somebody had brought in a swan, which turned out to have avian flu and contaminated everything.’
He added: ‘At the end of the day, it’s the national flock we’ve got to
‘I’ve never seen anything like this. It knows no boundaries’ ‘From the ecological perspective, it’s terrible’
protect; it’s not just laying hens, it’s broilers, it’s turkeys and we need to make sure we produce enough food to keep the shelves filled.’
The aftershocks of this disaster are also reverberating through other industries. Gamekeepers are looking nervously towards the approaching shooting season – worth £1billion to the economy – as the virus has ripped through mainland Europe causing a lack of French imports of pheasants and partridges for UK shoots.
Colin Morrison and his father, Iain, who run Turus Mara boat tours from Mull’s west coast, have had to rearrange trips to circumnavigate rather than land on the Treshnish Isles, which have significant storm petrel colonies.
Colin, 50, said: ‘Some of my earliest memories are going down to see the birdlife on the Treshnish Isles and the last thing we want to see is its decimation. Our business may depend on the wildlife, but we also care deeply about it.
‘At the moment, we don’t seem to be so badly affected, but you can’t be sure until you see what comes back next year. The effect on business is not catastrophic, but it could be by next year if we had to miss a whole season. Clearly we are very worried about the situation, never mind the business. This all feels very personal.’
Back at Troup Head, meanwhile, the plaintive cries of the surviving gannet chicks are growing fainter.
The race is on to save them being silenced for good.