Black eyes in seabirds indicates bird flu survival - RSPB
- Scientists have discovered evidence that Northern Gannets can recover from bird flu and that unusual black iris coloration is linked to a previous HPAIV infection
- The study also assessed the impact of HPAI on adult gannet survival at the largest gannet colony in the world - the Bass Rock, UK
- The team found that at Bass Rock, adult survival between 2021 and 2022 was 42% lower than the average over the previous 10 years.
A new study has discovered evidence that Northern Gannets can recover from Highly Pathogenic Avian Influenza (HPAI) H5N1, with black irises, an indicator of a previous infection.
Scientists from multiple organisations investigated outbreak timings at colonies across their North Atlantic range. At their largest colony, Bass Rock, UK, a detailed study was conducted to estimate the impact of the virus on colony size, breeding success, adult survival, and whether Gannets were potentially able to recover from an infection.
Black irises – instead of the usual pale blue – were first seen in Gannets breeding on the Bass Rock in June 2022 with colour varying from completely black to mottled. The team took blood samples from 18 apparently healthy adult Gannets with both normal and black irises, which were tested for bird flu antibodies by APHA to determine whether the birds had been previously infected. Eight tested positive, of which seven had black irises.
Dr Jude Lane, RSPB Conservation Scientist and lead author of the study: “This has been a fascinating development and the discovery may prove a useful non-invasive diagnostic tool. The next steps are to understand its efficacy, if it applies to any other species and whether there are any detrimental impacts to the birds’ vision. Ophthalmology exams will also be needed to determine what is causing the black colouration.”