New data has shown that a deadly virus killing the blackbird population has spread across the south of England in just five years. Speaking to the BBC an ornithologist said that it was inevitable that the devastation would continue around the country.

Mya-Rose Craig, from the Chew Valley in Somerset, said the spread of the Usutu virus shows British wildlife is struggling “in a way people don’t realise”. Ms Craig, 23, who is known as BirdGirlUK on social media, has been campaigning for the environment since the age of 13. She said: “One of the reasons [blackbird decline] concerns me is because it’s getting worse because of climate change.”

In the last five years blackbird populations in Greater London have fallen as much as 40%. Ms Craig, who was awarded an honorary doctorate by the University of Bristol in 2020, told BBC Breakfast: “My biggest concern is that blackbirds are one of the most common species in the UK, they are everywhere.

“When you hear bird song, it’s quite often blackbirds that you are hearing, so I think [their decline] is quite upsetting.” Experts are asking people in the UK with gardens to do two things - make them more friendly for birds and also take part in a major survey so the British Trust for Ornithology (BTO) can track the decline.

Ms Craig said “Our garden species are so special, which is why I find it so worrying - the speed of decline we are experiencing at the moment,” she said.

“Our wildlife is really, really struggling in the UK in a way I don’t think people really realise.”

Experts say the UK’s warm, dry springs – 2025 was officially the sunniest since records began more than a century ago – force those creatures deeper underground and bake the soil hard, so that blackbirds cannot find the food they need for themselves and their growing chicks - meaning people can help with appropriate food.

How will Blackbirds in Gardens help?

This survey will help the BTO understand the potential for disease transmission by Blackbirds in gardens by looking at the number of birds that occur together. The group said it will aid in understanding how Blackbird’s use of different types of gardens varies, and how well young can be raised, especially at different levels of urbanisation from rural to urban gardens.

The BTO said: "Although largely harmless to humans, this is the first time in modern history that a mosquito-borne viral zoonosis (a disease which can be transmitted from animals to humans) has emerged in wild animal hosts in the UK but, with changing climates, more may occur in the future.

"Using Usutu virus and Blackbirds as a case study, this survey is part of the Vector-Borne RADAR project, a wider partnership project funded by the UKRI and Defra to understand the emergence and transmission of mosquito-borne viruses in the UK more generally which are expected to increase with climate change.

"The project will improve understanding of how these viruses emerge in new environments, enhance surveillance of diseases in wild birds in the UK and develop an early warning system for disease outbreaks."

This survey will take place to September 2025.

How to sign up to the survey

You can sign up for Blackbirds in Gardens online.

How you can help blackbirds

There are several things you can do to help reduce the spread of the Usutu blackbird virus. RHS Senior Wildlife Expert Helen Bostock and Senior Ecologist Caitlin McLaughlin share their top tips.
 

• Minimise unnecessary standing water in your garden where mosquitoes could breed: stand wheelbarrows up when not in use to avoid rainwater collecting, put away any plant saucers when not in use, ensure gutters are kept clear of blockages, and ensure lids are fitted to water butts (this also reduces the risk of wildlife drownings).

• Wash out bird baths regularly, refilling with clean tap water. Clean and disinfect bird feeders every week to remove any build-up of food and droppings, and sweep the area around and below any bird feeders and tables. Maintaining good hygiene at the feeding area will also help to reduce the spread of other bird diseases such as the trichomonosis that has decimated greenfinch and chaffinch populations.

• Keep an eye out for unusual behaviour or deceased blackbirds – symptoms include lethargy, weakness, loss of coordination and seizures. You can report signs of disease, or finding a dead blackbird, to Garden Wildlife Health. Although Usutu is not a notifiable disease, meaning it doesn’t officially have to be reported, this will help scientists track its spread. If you need to move or handle a dead blackbird, or nearby feathers or droppings, wear disposable gloves or a plastic bag over your hand and thoroughly wash your hands with soap and water afterwards.