Dozens of cats across the U.S. have tested positive for avian flu, federal officials say. The west coast has been hit especially hard.

The Wild Felid Advocacy Center in Shelton, Washington, about 80 miles west of Seattle, cares for displaced wild felines, such as cougars, bobcats, servals, tigers, lynxes and more. The nonprofit lost 20 cats since November. Animal health officials confirmed the cause was avian influenza, according to their Facebook.

Bird flu has taken a terrible toll at the Wild Felid Advocacy Center, a sanctuary for wildcats and their hybrids on Harstine Island, Washington, killing 20 cats—half the animals in its care.