At least 20 California condors have died of avian flu in recent weeks, and wildlife officials are preparing for the virus’ spread among the critically endangered birds. The highly contagious H5N1 bird flu that is killing North America’s biggest bird is the same strain that forced farmers to cull millions of chickens over the last year.
It is a major blow to the population of California condors (Gymnogyps californianus), which were pushed to the edge of extinction in the 1980s. Intensive breeding and habitat conservation efforts have since bolstered their numbers to around 500 birds, around 300 of which live in the wild. Clusters of the giant vultures can now be found from western Canada down to northern Mexico.
In recent weeks, the US Fish and Wildlife Service had confirmed at least 20 condor deaths in a flock located around Arizona and Utah. So far, 10 of the condors in that flock have tested positive for avian flu and the 10 remaining birds are currently undergoing examination. The deaths represent a 7 per cent loss of the species’ wild population.
As of 17 April, the US Fish and Wildlife Service was rehabilitating four condors from the flock in the south-west US. They were “receiving supportive care and have shown improvement”, according to a statement.
“My worry is that avian flu could spread throughout the regional condor groups as the disease becomes more prevalent in bird populations in general,” says Ileene Anderson at the Center for Biological Diversity in Arizona. “Since there is no known vaccine or proven treatment, at a minimum it could set back California condor recovery for years and at the worst it could decimate the population.”
Avian flu has not been detected in neighbouring flocks in California or Mexico’s Baja California peninsula. Officials say they are monitoring nearby condors and preparing in the event that it spreads, especially as migratory birds that could ferry the virus fly north for spring migration.
Though there have been rare cases of avian flu illness and deaths in humans, public health officials say that transmission is rare and advise avoiding close contact with sick or dead wildlife.