Overview

• The British Trust for Ornithology has launched a garden-based survey running through September 2025 to assess the virus’s impact on Blackbird populations across urban and rural areas.
• Blackbird numbers in Greater London have fallen by up to 40 percent since Usutu was first detected in the UK after the 2020 heatwave, with cases now confirmed from Dorset to Cambridgeshire.
• Participants are urged to report Blackbird sightings and nesting success in their gardens to help researchers map disease transmission and population trends.
• While no human cases have been reported and the current risk to people remains low, experts warn this outbreak could foreshadow other mosquito-borne diseases establishing in Britain.
• This survey forms part of the UKRI- and Defra-funded Vector-Borne RADAR project, which aims to improve surveillance and develop an early warning system for emerging mosquito-transmitted viruses.