Federal officials have been urged to vaccinate California condors against avian flu/Kurt Repanshek file

Nearly 30 organizations have asked the U.S. Fish and Wildlife Service and U.S. Agriculture Department to vaccinate California condors in the wild to protect them from avian flu, which already has killed at least 21 of the iconic birds.

"The United States is currently facing the largest outbreak of [highly pathogenic avian influenza, HPAI] in its history. This extremely infectious and fatal form of avian influenza is spreading through wildlife populations around the world, and has now begun to spread to the critically endangered California condor," reads the letter, sent Monday.

"On April 9th, the National Park Service reported that HPAI had killed three condors from the Arizona-Utah flock. In just eight days, the number of fatalities jumped to 20, with an additional condor death confirmed late last week," the groups added. "These deaths account for 17 percent of the entire Arizona-Utah flock, which numbered 116 birds before the outbreak."

The Arizona-Utah condor population moves throughout northern Arizona and southern Utah, using the landscape within Grand Canyon National Park, Zion National Park, Vermillion Cliffs National Monument, the Kaibab Plateau, and surrounding areas, according to the agency. The range for the endangered condor, the largest bird in North America, also includes Pinnacles National Park in central California.

The outbreak dates at least to early March. 

"On March 9, The Peregrine Fund, which manages the Arizona-Utah condor flock, first observed a bird in the wild exhibiting signs of illness, initially suspected to be lead poisoning. Crews continued to monitor this bird and others showing similar behavior. On March 20, they collected the deceased female below her nest, which was the first bird confirmed positive with [Highly Pathogenic Avian Influenza]," said Fish and Wildlife.

Potential exposure of HPAI is expected to rise during the spring migration of birds north to their breeding grounds. HPAI has been detected in all U.S. states, except Hawaii, in wild and domestic animals.

Possibly blocking the groups' request is that the United States currently has no approved vaccines against the current strain of the disease, the groups noted. However, they added,"a vaccine has already been approved for use in wildlife in other parts of the world."

"The ongoing threat to the California condor is clearly an emergency warranting" expedited development of a vaccine that could be rolled out under the Fish and Wildlife Service's emergency authorities.