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Avian Influenza: An Update

Gannets

We’ve been covering avian influenza, or bird flu, and its effect on wild bird populations since spring last year. The highly pathogenic avian influenza (HPAI) strain called H5N1 devastated many of our seabird colonies last summer following a winter of geese deaths. An estimated 200 million birds have died globally. Migration is considered one of the main contributors to the virus’ spread. So, with birds returning to the UK from their wintering grounds and the new breeding season about to get underway, here’s an update on the current situation. Head to the bottom of the page to find details of when and how to report any sick or dead birds found.

Bird Flu in 2021 and 2022

Bird flu is, of course, not a new phenomenon. Low pathogenic avian influenza (LPAI), usually non-fatal, has circulated in wild populations for some time. HPAI, however, has been restricted to outbreaks in domestic birds until recently. The current outbreak of HPAI in wild birds is unprecedented, affecting multiple regions and species. Thought to originate in intensive poultry farms in China, it first came to the attention of conservationists in the summer of 2021. Dead great skuas, or bonxies, were found in Shetland, Orkney and St Kilda at the end of the summer and many tested positive for the virus. The Svalbard population of barnacle geese wintering on the Solway Firth was hit next. An estimated 16,000 died during the winter of 2021/22, over a third of this particular population. Pink-footed geese migrating up Scotland’s east coast were then thought to spread the disease to other species including eiders and herring gulls. There was also the largest outbreak on record in UK domestic birds over the winter of 2021/22.

Great skua or bonxie
Great skuas were first hit by bird flu in 2021

Worse was to come over the summer of 2022, however. Bird flu is usually more of a concern during the winter but the 2022 breeding season was catastrophic for seabird colonies around the UK. Multiple species were affected, although some colonies managed to escape the worst of the outbreak. Great skuas were again hit hard, with reports of over 2,000 dead last year. This is extremely worrying for the species as the UK holds approximately 60% of the global breeding population. Gannets were also one of the most affected species. They may, though, be more resilient as a result of their much bigger numbers. Nearly 25% of Britain’s only breeding roseate tern colony on Coquet Island, Northumbria, died as did an estimated 75% of Sandwich tern chicks at Scolt Head, Norfolk. Razorbills, guillemots, kittiwakes and herring gulls were some of the other worst affected birds. More than 50,000 wild birds may have died so far in the UK between October 2021 and April 2023. There were also increasing reports of the disease in mammals, including seals and red foxes.

Gannets avian influenza
Gannets were one of the worst hit species last summer due to their crowded colonies

The Current UK Situation

This winter the biggest losses have been in the Greenland barnacle goose population. This group winters predominantly on Islay and the nearby islands of Coll, Colonsay and Oronsay. At least 900 deaths have been recorded, but this may not represent the full scale of fatalities. The biggest casualties so far this spring are gulls at a number of inland breeding colonies in central and northern England. The risk of domestic outbreaks also remained high over the winter. Mandatory housing measures for captive birds and poultry were only lifted in England and Wales on April 18th this year. Strict biosecurity practices are still recommended, however. These include reducing the movement of people and equipment into areas where birds are kept, thorough disinfecting of clothing and equipment following contact with captive birds, regular cleaning and disinfecting of bird housing and continued vigilance to signs of disease.

Barnacle Goose avian influenza
The Greenland breeding barnacle goose population has suffered losses this winter

Currently, conservationists are awaiting the breeding season with trepidation. There is evidence that some gannets caught the virus last year but survived. This has been tested in birds with the characteristic darkened eyes of bird flu victims. They may now possess some measure of immunity that can be passed to any offspring. The National Trust has already announced that it won’t be opening the Farne Islands to the public until at least August in an effort to reduce the stresses on vulnerable species. Over 6,000 bodies were collected there last summer, with guillemots affected most on the islands. Once the breeding season is underway, we will have a clearer idea of how much populations were impacted by last year’s losses, however. Environment organisations, both governmental and from the charity sector, are continuing to work together to understand how best to protect wild birds from the worst of the disease. This April, NatureScot published an in-depth report into the virus in Scotland. This aims to provide advice to Scotland’s Avian Flu Task Force, set up in July 2022. The report concluded that long-term conservation measures are vital in helping reduce the impact of HPAI on wild bird populations.

The Global Situation

The current outbreak reached the Americas in November 2021. First detected on Canada’s eastern seaboard, it subsequently spread west and south. Detected in every US state bar Hawaii, it is now affecting birds in Central and South America. Worryingly, an increasing number of mammal species are being killed by the virus in the Americas. This includes approximately 3,500 South American sea lions dying of bird flu in Peru since November 2022. Scientists don’t yet know if they caught the disease from seabirds, although this seems a likely scenario. There are also concerns that infected sea lions could pass the virus to those species they have contact with that migrate to Antarctica, taking the disease there.

Red foxes avian influenza
Red foxes are just one of the mammals that have been recorded with HPAI

This spring, the disease was also detected in six dead Californian condors, with more cases suspected but unconfirmed. At present only birds from a population moving between Arizona and Utah have been affected but the species is extremely rare, with only around 500 alive in the world, including captive birds. Closer to home, Senegal and The Gambia reported thousands of bird deaths in recent weeks. Great white pelicans, royal terns and great cormorants are among those affected. The region’s domestic poultry have also been hit. Both countries are on the migration routes of millions of birds that head north to breed. This had led to fears that this will lead to yet more outbreaks in Europe and another devastating summer for wild birds.

Finding Sick or Dead Birds

Bird flu is very much still with us and so it is important to know what to do should you find a sick or dead bird.

Most importantly, do not touch or handle any sick or dead birds you come across. If you have a dog, do not let it near any bird carcasses either.

In England, Scotland and Wales, if you find one or more dead bird of prey, swan, goose, duck or gull, or five or more wild birds of any species you should report them to Defra via the online reporting system here or by telephone on 03459 335577.

In Northern Ireland, ring DEARA on 0300 200 7840.

To help assess how avian influenza is affecting non-birds, dead animals can also now be reported in England, Wales and Scotland. There are guidelines here for reporting dead non-avian animals that may have been affected by bird flu in England and Wales.

In Scotland, a list of susceptible animals has been issued. If you find a dead otter, pine marten, fox, stoat or weasel, report to NatureScot. Dead cetaceans and seals can be reported to the Scottish Marine Animal Stranding Scheme.

Purple Plover will continue to cover the outbreak in the coming months. Keep an eye out for our monthly news round-ups for any developments.