A mass mortality event suspected to be caused by the deadly H5N1 bird flu virus has been reported in Australia, with over 80 dead and sick birds found on rocks off the South Australian coast. This comes just six weeks after the disease arrived in the country. Authorities have reported 49 dead greater crested terns on Baudin Rocks, near Robe, as well as 35 more sick terns.
While some of the birds had been collected for testing, South Australia’s chief vet Skye Freuan said it was likely the first mass mortality event from the disease. South Australia also reported three suspected positive cases in other greater crested terns, including one inland at Monarto, suggesting the disease has begun moving away from the coast. The Monarto area is home to several poultry farms.
Three silver gulls were also suspected positive, adding to the first silver gull found a few days ago and confirmed positive by the CSIRO earlier on Saturday. Kate Millar, the chief executive of conservation charity BirdLife Australia, called it a “very significant escalation of the bird flu situation in Australia, and a very bleak milestone”. “Sadly, we’re at the beginning of a long and challenging battle and birds and wildlife are going to need all the help they can get,” she said. The cases among silver gulls have experts concerned that the spread of the virus has now reached a critical new stage.
Sean Dooley, the national affairs adviser at BirdLife Australia, noted that silver gulls are very common, primarily coastal, but they do come inland and can turn up in Lake Eyre following floods. They also scavenge from dead or dying animals, meaning they can easily pick up the disease from other sick birds, and pick detritus from water bodies – lakes and flooded areas included – and these are known to be breeding grounds for the disease. “There is such a large population of silver gulls, and they move into other habitats. They could be the vector that takes bird flu inland,” says Dooley. “They’re also really successful in urban areas and could bring the disease into those bird populations.” Because Australia has a high concentration of unique birds, the susceptibility of many native species isn’t known.
But the fears are there is no reason to think they would manage any better than birds overseas. Birds that flock around water have tended to be the hardest hit. Examples include sandwich terns, black-headed gulls and northern gannets in Europe and, in Peru, pelicans.
Dooley said the mood at BirdLife Australia this week had been one of “trying to suppress that sinking, gut-churning feeling”. The winter season for birdwatchers along the coast had been one of the best in 10 years, said Dooley, with rare petrels turning up in numbers along the east coast. “Now that has been heavily tinged because probably among those were birds carrying H5N1.”
