Concerns Grow Over Mosquito-Borne Virus Affecting Blackbirds in the UK
A newly arrived mosquito-borne disease in Britain is raising alarms as it spreads over significant distances, with scientists eager to assess the implications for wild bird populations.
The Usutu virus, transmitted by infected mosquitoes, poses a threat especially to blackbirds, a species well-known for its cheerful song. Recent findings indicate that Usutu has made considerable strides across southern England in just five years, and there are concerns about its correlation with declines in certain blackbird populations.
Experts are closely observing the virus’s spread, particularly as climate change seems likely to influence the range of mosquitoes and the diseases they might carry. Dr. Arran Folly from the Animal and Plant Health Agency (APHA) noted, “The virus is now extending its reach beyond our initial expectations and appears to be establishing itself.”
Researchers at APHA have been monitoring mosquito-borne illnesses in wild birds for many years, especially in light of warnings suggesting that climate change could turn Europe into a more suitable environment for these insects.
With longer summers and heavier rains, conditions increasingly allow these pesky creatures to inhabit areas that were once considered uninviting for them. Prior to 2020, no signs of the virus had been detected. But during that summer’s heatwave, Usutu was discovered in multiple blackbirds around Greater London.
Dr. Folly expressed concern, stating, “Blackbirds are particularly vulnerable to the infection, and since 2020, we’ve observed about a 40% decline in their numbers in Greater London.” He added that this situation could hint at the potential emergence of additional mosquito-borne viruses in the UK.
Viruses like Usutu now represent a significant threat to wild birds already facing various challenges, including habitat reduction, climate shifts, and pesticide application.
Understanding Usutu Virus
- The Usutu virus was first identified over 50 years ago near the Usutu River in southern Africa.
- It has since made its way around the globe, reaching Europe three decades ago, with its first detection in the UK occurring in 2020.
- Blackbirds are most affected by this virus, although it can also infect horses and, on rare occasions, humans.
Recent data reveals that Usutu has spread more extensively than anticipated. It’s now been found in wild birds throughout a wide area of southern England, extending to places like Dorset and Cambridgeshire. However, the exact risk it poses to wild birds remains uncertain. The virus has previously triggered mass die-offs of blackbirds in various parts of Europe, but this trend isn’t currently evident in Britain. The blackbird continues to be one of the most commonly seen birds in gardens, maintaining stable populations in many regions, especially rural and northern areas.
To help solve this puzzle and gather further information regarding blackbird populations, scientists are collaborating with the British Trust for Ornithology (BTO). They are inviting volunteers to monitor blackbirds in their gardens during the summer months to better understand these birds’ movements.
This time of year, blackbirds are busy breeding and nurturing their young, often spotted hopping on the ground or singing from tree branches during pleasant summer evenings.
Lucy Love, a birdwatch ambassador for BTO, has developed a fondness for the blackbirds in her garden, commenting, “They’re stunning creatures—smart, sociable, and their songs are wonderfully melodic.” She emphasized, “We cannot afford to lose them; they play a crucial role in our ecosystem.”
