Three California condors have died from bird flu in northern Arizona, the National Park Service announced Friday, and authorities are trying to determine what killed five others in the flock.
A sick female bald eagle with suspected lead poisoning was found dead on March 20 and tests showed it was infected with highly pathogenic avian influenza (HPAI), the park service said.
Two other birds that were later found dead also tested positive, the park service said, while test results for five others are pending.
The birds are part of a population that migrates throughout northern Arizona and southern Utah, including Grand Canyon National Park, the park service said.
The Peregrine Foundation, which manages the Arizona-Utah flock, also captured five other birds that appeared to be sick and sent them to a wildlife rescue center in Phoenix. One bird died and four others have been quarantined, officials said.
Exposure to the virus is expected to increase during the spring northward migration of bald eagles.
HPAI has not been detected in other populations in California or Baja California, Mexico, according to the park service.
Avian influenza occurs primarily in birds, including chickens, but other wild and domestic animals have been found in every U.S. state except Hawaii.
Humans are considered to be at low risk of infection with HPAI, although infections have been reported.
The California condor is one of the largest birds in the world, with a wingspan of up to 10 feet (3 meters). These birds once patrolled the skies from Mexico to British Columbia. Condors can live up to 60 years and fly great distances, which is why their range can stretch across several states.
In the 1970s, the population plummeted to the brink of extinction due to hunting, habitat destruction, and lead poisoning of animals eating lead bullets.
In the ’80s, wildlife officials captured the last 22 bald eagles left and brought them to zoos in San Diego and Los Angeles for conservation and captivity. The birds are then released into protected areas and national parks, where they can be monitored.
These birds have been protected as endangered species since 1967, federal law and California state law since 1971.
California condors have been making a comeback in the wild and now occupy parts of California’s Central Coast, Arizona, Utah and Baja California, Mexico. The total wild population now exceeds 300.