Avian flu kills 20 California condors in Arizona, Utah

Twenty California condors in northern Arizona and southern Utah have died since March and half of the endangered birds tested positive for a strain of avian flu, according to authorities.

Four condors are still receiving supportive care and have shown improvement, but wildlife officials told The Arizona Republic that they’re worried the recent outbreak could potentially spread to other condor populations.

So far, authorities say, the virus hasn’t been detected in the other condor populations in California or Baja California, Mexico.

The Peregrine Fund, a group that manages wild populations of the bird, estimates there are 116 wild condors flying over Arizona and Utah and occupying the landscape within Grand Canyon National Park, Zion National Park, Vermillion Cliffs National Monument, on the Kaibab Plateau and in surrounding areas.

"The condor is slow to mature, taking up to eight years before they can produce young, and with an average of one young every other year, the rate of replacemen...