Homeowners with blackbirds in garden warned to take action

Daily Record

16-05-2025

The Usutu virus, which can be transmitted by infected mosquitoes to blackbirds, has raised concerns for the well-being of the birds
A mosquito-borne disease that has recently been detected in the UK has seen a rapid spread, posing a potential threat to native bird species. The Usutu virus, known for affecting blackbirds, has stirred concern amongst scientists regarding the wellbeing of these beloved songbirds.
The latest figures suggest that over the past five years, the Usutu virus has spread widely throughout southern England, correlating with a noticeable drop in some blackbird populations. With climate change potentially allowing mosquitoes and their associated diseases greater leeway to extend their reach, experts are vigilantly assessing the situation.
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Researchers are calling on people who observe blackbirds in their gardens to aid in a special counting initiative to gauge the impact of the Usutu virus on blackbird numbers. The British Trust for Ornithology explained: "The Blackbirds in Gardens project will help us understand how Blackbirds use gardens, and the potential effects of the Usutu virus on their population in the UK."
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Further explaining the initiative, the BTO said: "If you have access to a garden, have an interest in garden birds and can recognise a blackbird by sight, then this survey could be for you!" This newly introduced survey is set to continue until September, reports Chronicle Live.
The Vector-Borne RADAR initiative has teamed up with the Animal and Plant Health Agency, the UK Health Security Agency, and the Zoological Society of London, as reported by the Express.
"We've seen that the virus has spread further than we thought it might do, and it's persisted," said Dr Arran Folly from the Animal and Plant Health Agency (APHA) in a conversation with the BBC. The APHA specialists in Weybridge, Surrey, have been tracking the prevalence of mosquito-borne diseases in wild birds for years, concerned that climate change could be turning Europe into a more inviting environment for the insects.
Worsened by extended warm periods, climbing temperatures, and significant rainfall, Europe is witnessing conditions that welcome mosquitoes to regions previously inhospitable to them. Until 2020, surveillance efforts yielded no positive findings.
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Nevertheless, in the aftermath of 2020's heatwave, the presence of Usutu was verified in multiple blackbirds throughout Greater London. "Blackbirds specifically are quite susceptible to the virus and since 2020 we've found a decline in blackbirds of approximately 40-per cent in Greater London," revealed Dr Folly.
He warned: "It gives an indication that in the future we might get other viruses that are transmitted by mosquitoes emerging in the UK."
The health of wild birds is under increasing threat, challenged not only by diseases like Usutu but by habitat destruction, alterations in climate, and pesticide usage as well.
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What is Usutu?
The Usutu virus was first identified over fifty years ago near the Usutu River in southern Africa. It has since spread globally, reaching Europe three decades ago, and was detected for the first time in the UK in 2020.
Blackbirds are particularly susceptible to the virus, which can also affect horses and occasionally humans. The virus is generally considered low risk to humans, with no reported cases in the UK to date.
It has now been found in wild birds across a large area of southern England, extending as far west as Dorset and as far north as Cambridgeshire.
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The exact threat Usutu poses to wild birds remains unclear. The virus has been associated with mass blackbird deaths in other parts of Europe, but this doesn't seem to be the case in the UK.
The blackbird continues to be one of the most common garden birds, with stable populations in many regions, especially in rural areas and the north. To solve this mystery and gather more data on blackbird numbers, scientists have partnered with the British Trust for Ornithology (BTO).
They're appealing for volunteers to count blackbirds in their gardens over the summer months to gain further insight.
During this season, blackbirds are actively breeding and raising their young. They can often be seen hopping along the ground or singing from tree branches on warm summer evenings.