The U.S. Department of Agriculture said separate strains of the H5 virus were identified in a northern pintail duck and a gyrfalcon.
Both viruses have been found in other parts of the world and have not caused any human infection to date, the USDA said. Neither virus has been found in commercial poultry in the U.S.
An avian influenza outbreak this month in southwest British Columbia spread to several poultry farms, and 155,000 birds have died of the virus or will be euthanized, Canadian officials said last week.
"There's really no reason to panic. This does not represent an increased risk to people," said Dr. Kristin Mansfield, a veterinarian with the Washington Department of Fish and Wildlife. "There's very little to no risk of these viruses affecting people."
The state's two confirmed cases are a captive falcon with the H5N8 strain of avian flu, and a wild duck with the H5N2 strain, said Hector Castro, a spokesman for the state Department of Agriculture. The falcon had been fed wild birds killed by hunters.
Castro said that after the Canadian outbreak, the state stepped up random testing in domestic poultry flocks near the border and put out information to other bird owners. The falcon was diagnosed after its owner took it to a veterinarian, who then reported its death to the state. A USDA lab in Iowa confirmed the virus over the weekend.
According to the Centers for Disease Control and Prevention, there was an outbreak of the H5N2 virus in a flock of chickens in Texas in 2004. That was the first outbreak of highly pathogenic avian influenza in 20 years, the CDC said.
In Washington, the viruses were detected in Whatcom County, which is on the Canadian border, but Mansfield said officials do not yet know whether the flu spread from British Columbia.
"There are many strains of avian influenza, and it is not uncommon for wild waterfowl to carry the virus," said Dr. Joe Baker, Washington's state veterinarian. He said it's critical for poultry owners to take steps to protect their birds from wild fowl.
The bird flu strain that has caused the most global concern is H5N1, which began ravaging poultry across Asia in 2003 and is more easily spread among humans.