Boobies with black irises in Blackrock, Scotland
Jude Lane/RSPB
Some seabirds may have blackened blue eyes when infected with bird flu.
Color changes seen in boobies (Kwabasanus), which may provide scientists with a new way to track the impact of virus outbreaks.
Avian influenza has been circulating seasonally in wild and farmed birds for decades, but since October 2021, a highly pathogenic strain of the virus has transformed wild and farmed bird populations into an unusual pathogen. dominated by sex.
European and British seabirds have been particularly hard hit, with thousands of birds including endangered boobies, puffins and monitor lizards dying from the H5N1 virus in the past year.
For example, adult survival for the 150,000 boobies population on Bass Rock, an island off the east coast of Scotland, was 42% below the average for 2021-2022.
Scientists have struggled to determine whether seabirds survived the infection or have so far escaped contact with the virus without conducting invasive tests.
Collecting this information will help us better understand how the virus is affecting wild bird populations, including assessing survival rates and whether these birds are developing immunity to the disease. It is important.
Boobies with black or mottled black irises, rather than the standard pale blue color, have been spotted for the first time in several colonies known to have been affected by bird flu, including the UK, France, Germany and Canada. rice field.
Jude Lane of the British conservation charity RSPB and her colleagues took samples from 18 apparently healthy boobies with normal and black irises in Bass Rock. Eight birds were antibody-positive for avian influenza, seven of which she had black irises.
The incidence of this trait could be useful as a noninvasive diagnostic tool for conservationists tracking the impact of avian flu, says Lane. “Because we can see not just how many birds are dead, but how many are surviving, we can add these details to our population model to see how future seabird populations will look like. “We can predict what will happen,” she says.
It’s unclear what caused the iris to turn black, but Lane and her colleagues are looking into this. She also plans to study whether the changes are permanent, how long viral antibodies persist in boobies, and whether birds suffer long-term adverse effects from the infection, such as fertility or visual impairment.
It will also be important to understand whether the same changes in eye color occur in other bird species, she added.
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