An epidemiological study found that 56% of a large breeding colony of Caspian terns died from a 2023 outbreak of highly pathogenic avian influenza at Rat Island in Washington state. Since then, no birds have successfully bred on the island, raising concerns that the outbreak may have had a significant impact on an already declining Pacific-coast population.
Washington coast avian flu outbreak devastated Caspian terns, jumped to seals
