Bird Flu Suspected in First Mass Die-Off of Wild Birds on Australian Coast
Dozens of greater crested terns found dead or dying off South Australia as H5N1 reaches the continent's wildlife just six weeks after its arrival
By Ada "Peer-Review" Sparks
Helicopter crews scanning the rocks off Robe, on South Australia's coast, counted 49 dead greater crested terns and another 35 sick ones on Baudin Rocks over the weekend. If confirmed, authorities say it would be the first mass mortality event caused by the H5N1 strain of avian influenza since the virus reached Australian shores roughly six weeks ago.
Australia had been one of the last major landmasses to escape the H5N1 clade that has torn through wild bird populations, poultry flocks and, in some cases, mammals across the Americas, Europe and Asia over the past several years. Its arrival here was expected by scientists who track the virus along migratory bird routes, but the speed of this apparent die-off — dozens of birds found sick or dead in a single colony within weeks of detection — will concern wildlife authorities and virologists watching how the pathogen behaves in a new ecosystem.
Greater crested terns nest in dense colonies, a trait that makes them, like many seabirds, especially vulnerable to fast-moving viral outbreaks. Mass deaths among colonial seabirds have been one of the signature and most visible impacts of H5N1 elsewhere in the world, from the coasts of Peru to the Northern Isles of Scotland, sometimes wiping out large fractions of local breeding populations in a single season.
The report so far rests on aerial survey data described by authorities on Saturday; confirmation of H5N1 as the specific cause in these birds — as opposed to a related strain or another illness — will depend on laboratory testing of samples, which has not yet been reported publicly. Readers should treat the H5 identification as preliminary until officials publish confirmed lab results, and until the scale of the die-off across the wider colony is established.
What's not in dispute is the pattern: a virus that spread from poultry farms to wild birds worldwide is now testing Australia's isolation, and the answer will matter for native species with nowhere else to breed.
Extraordinary claims. Ordinary evidence? Then no.
— Compiled from reporting by The Guardian.
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