New research from the RSPB indicates that two major global gannet breeding sites will require nearly two decades to rebound from a severe H5N1 avian influenza outbreak in 2022. The study details how Bass Rock near Scotland and Grassholm in Wales experienced a catastrophic loss of life, with adult mortality rates surging fourfold. This resulted in population declines of 26% and 38% at these respective sites.
Although thousands of birds perished during the initial surge, the long-term prognosis is equally concerning, with full population restoration not anticipated until at least 2041. Researchers noted that because colony expansion relies heavily on adult breeders, the high death rate will suppress growth for years. Consequently, experts are calling for a reassessment of the Northern gannet’s status on the IUCN Red List, which currently classifies the species as of least concern.
Jude Lane, the study’s lead author and an RSPB marine conservation scientist, emphasized that while disease outbreaks are difficult to curb, rigorous monitoring is essential. She noted that gathering data on these colonies will help conservationists mitigate other stressors and counteract the general decline of UK seabird populations. The RSPB recently acquired Bass Rock, which holds the world’s largest colony, marking the end of 320 years of private ownership by the Hamilton-Dalrymple family.
