'Significant escalation': Mass mortality events leave over 1,000 birds dead in South Australia

Authorities in South Australia have identified three mass mortality bird events. The events involve more than 1,000 crested terns, which authorities "presumed" died of the H5N1 bird flu.

The deaths, detected on Wednesday, occurred on remote islands including Troubridge Island, as well as North Page and South Page close to Kangaroo Island.

State government surveillance teams discovered the dead birds, and are considered a "significant escalation" of bird flu cases in the state, South Australian Premier Peter Malinauskas said in an address to the SA parliament.

"The loss of more than 1,000 birds is deeply concerning, and the state government is treating these events with the utmost seriousness," he said.

"Of particular concern, we are also investigating a suspected case involving a little penguin from Kangaroo Island."

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Malinauskas said that no similar mortality events had been reported in mammals. He also noted that H5N1 had not yet been detected in any poultry or livestock.

South Australia has recorded 177 confirmed H5 bird flu cases as of Friday 21 August.

A surveillance team found 28 little penguins had died, along with three crested terns, a week after the H5 bird flu strain was first detected in the state.

The virus was found for the first time in Tasmania last Thursday in a brown skua at Rocky Cape on the north-west coast returned a postive test.

Silver gulls and crested terns have been found dead in the days since.

Seven of the state's 11 confirmed deaths have happened on King Island.