CNN
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A new strain of highly pathogenic avian influenza – commonly called bird flu – has killed around 1,600 snow geese in two separate areas of Colorado since November, according to state wildlife officials.
Unlike prior strains of the disease in North America, this strain is “causing widespread mortality in some species of wild birds, particularly in snow geese, raptors, and vultures,” Colorado Parks and Wildlife spokesperson Bill Vogrin said in a statement to CNN on Monday.
The agency began receiving reports of sick and dead snow geese in northeastern Colorado in late 2022, the statement said. It documented over 1,000 deaths on several waterways in Morgan and Logan counties.
Then officials heard of “large-scale mortalities” in the southeastern portion of the state.
“There was a die-off of approximately 600 snow geese at John Martin Reservoir,” the statement said, noting lower die-offs at surrounding reservoirs.
After highly pathogenic avian influenza has been confirmed in a certain species and county, the wildlife department will not test additional birds of that species within that county until the next season – but additional deaths are still counted, the statement said.
Birds carrying the disease can carry it to new areas when migrating, potentially exposing domestic poultry to the virus, the US Department of Agriculture says.