SAN DIEGO – California’s endangered condors may have “virgin births,” according to a study released Thursday.
Researchers from the San Diego Zoo Wildlife Alliance said genetic testing confirmed that two male chicks hatched in 2001 and 2009 from unfertilized eggs were related to their mothers. Neither was related to a man.
The study was published Thursday in the Journal of Heredity. It is the first report of asexual reproduction in California condors, although parthenogenesis can occur in other species ranging from sharks to honey bees to Komodo dragons.
But in birds, it usually only happens when the females don’t have access to the males. In this case, each mother condor had previously interbred with males, producing 34 chicks, and each was housed with a fertile male at the time they produced eggs by parthenogenesis.
The researchers said they believe it is the first case of asexual reproduction in any bird species where the female had access to a mate.
“These findings now raise questions about whether this could occur undetected in other species,” said Oliver Ryder, study co-author and director of conservation genetics for the San Diego Zoo Wildlife Alliance.
The nonprofit alliance manages the San Diego Zoo and Safari Park and has been involved in a California condor breeding program that helped rescue giant vultures from near extinction.
With a wingspan of 10 feet (3 meters), California Condors are the largest flying birds in North America. They once spread all over the west coast. But only 22 survived in the 1980s when the United States government captured them and placed them in zoos for captive breeding. About 160 were raised at the San Diego Zoo and Safari Park.
There are currently more than 500 California condors, including more than 300 that have been released into the wild in California, Arizona, Utah, and Mexico.
Asexual reproduction was discovered a few years ago during widespread testing of genetic material collected over decades from condors, both living and dead, in breeding programs and in the wild.
“Among the 467 male California condors evaluated in the kinship analysis, no male qualified as a potential father” of the two birds, the study said.
California condors can live up to 60 years, but both males were sick. One was less than 2 years old when he died and the other lived less than eight years.