Avian circoviruses and hepadnaviruses identified in tissue samples of various waterfowl.

North America is home to over 40 species of migratory waterfowl. Utilizing tissue and cloacal-swab sampling from hunter-harvested carcasses in 2021-2023, we identified circular DNA viruses associated with 116 waterfowl samples from nine species (American wigeons, Mexican ducks, northern shovelers, northern pintails, canvasbacks, mallards, American black ducks, gadwalls, and green-winged teals). We determined the genome sequences of viruses in the families Circoviridae (n = 18) and Hepadnaviridae (n = 2) from the 13 virus-infected birds.