Gulls have become a new source for spreading avian flu in the wild, the expert leading Britain’s fight against the disease has told i.
According to Prof Ian Brown, scientific services director at the Animal and Plant Health Agency, the H5N1 virus behind avian flu, has changed to make it more easily carried by gulls.
Gulls present a particular risk because they are present everywhere across the UK, from inland farms to the most remote seabird colonies. This means that they can spread the illness between domesticated populations and wild ones.
Britain’s populations of sea birds, including internationally rare species, have been devastated by avian flu in the past 18 months, while 48 million farmed birds have been culled in the UK and Europe since December 2021.
Poultry farmers across all of England were forced in November to move their birds indoors by Defra in an attempt to slow the spread of the virus, with Wales following suit in November. All of Scotland has been under preventative measures since December.
Prof Brown told i: “There are some hosts in the wild birds that we’ve learned – things like gulls, so gulls are ubiquitous, they’re found around freshwater areas they’re found near poultry farms, but they also get out to remote sea islands where sea birds nest.
“Prior to this current H5N1 [virus] gulls have always been known to be susceptible to flus, but they do seem to be potentially a more regular feature in terms of this virus than they have been in the past.
“It does look like there’s been a bit of a shift in terms of the virus is actually quite happy to be in a gull as well.
“That obviously opens up other opportunities for spread. So not only does it increase the opportunity around poultry farms, another major population… you’ve also got a population [in gulls] that’s quite mobile and moves out and then takes the virus into seabird colonies, which are a bit like poultry houses, because the virus transmits very far.”
More than 2,200 Great Skua deaths were reported in Scotland in 2022, representing 7 per cent of the total global population.
The breeding season is yet to start in Britain for most species, so conservationists are anxiously awaiting their return to the UK when they will be able to assess the full impact of the disease and whether there will be a second wave this year.
The National Trust announced last month that it would not reopen the Farne Islands, a major site for seabird colonies, to visitors because of the worsening effects of avian flu. Last year, 6,000 dead seabirds were collected on the islands.
Claire Smith, the RSPB’s senior policy officer on avian influenza, told i that it was important to remember that the disease was the result of human actions and that wild birds were “victims not simply vectors” of the disease.
“This includes gulls, some of which – herring gulls for example – are red-listed species and have suffered significant losses in areas of Scotland this winter,” she said.
“There are likely to be multiple routes of [virus] transmission between wild birds, which will include bird movements. But [the virus] is originally a human-generated issue, originating in high-intensity poultry and duck farms in Asia.”
She also pointed out that the UK is a signatory to UN conventions which prohibit the culling of wild birds or anti-virus actions which damage the natural ecosystem.