Members of the public and charity volunteers are working to contain a suspected outbreak of bird flu among swans in the Thames Valley, amid signs that confirmed cases are continuing to rise.
Since October, 324 cases of bird flu in swans have been recorded by the Animal and Plant Health Agency (Apha), which is sponsored by the Department for Environment, Food and Rural Affairs (Defra). Of these, 39 were recorded in the first four weeks of 2026 alone.
However, there is growing concern that official figures may underestimate the true scale of the outbreak. The animal charity Swan Support said 46 dead swans had been found in the borough of Windsor and Maidenhead since 17 January, along with a further 26 in Newbury. Two swans were discovered dead in Windsor on Thursday, with three more found on Friday in the Berkshire village of Hurley.
bird flu/swan chart
Wendy Hermon, the operations director at Swan Support, said the birds had been found “spinning around in circles [and] bleeding from the eyes”, as well as appearing lethargic, prompting suspicion that bird flu might be the cause.
The charity said some of the recovered bodies had been sent to Defra for testing, but confirmation of bird flu as the cause of death had yet to be received.
Since 2021, the H5N1 strain of bird flu has devastated bird populations across the UK. The virus is highly infectious, with scientists saying that a single bird can infect up to 100 others, and that it can be transmitted through faeces, mucus, blood and saliva.
David Barber, the king’s swan marker, during the annual census, known as swan upping, on the River Thames. Photograph: Peter Nicholls/Reuters
David Barber, the king’s swan marker, who monitors populations of the birds, said: “It has been pretty grim and one of the worst years we’ve had for bird flu. We’ve had 40-plus swans that have died [in the Thames Valley region] but there’s probably double that number.
“Unfortunately, [Defra] haven’t come back and confirmed that it’s bird flu – [but] we all know that it’s bird flu.”
Hermon praised members of the public for being “amazing” in reporting suspected cases to the charity, which has been collecting the birds and removing them from waterways in an effort to contain the virus. Without such action, she said, “it’s likely that the virus will spread even more” to other bird species.
An Apha spokesperson said: “We are aware of reported wild bird deaths in the Berkshire area, and a number of swans have tested positive for highly pathogenic avian influenza.
“Members of the public are advised to not touch or pick up any dead or visibly sick birds that they find and should wash their hands thoroughly with soap and water if they touch wild bird faeces or feathers or after feeding wild birds.”
Swan Support echoed Apha’s guidance about not touching dead or sick birds, and hand-washing.
Members of the public are encouraged to report findings of dead wild birds online or contact Defra’s helpline on 03459 33 55 77.
