After Condor Chicks Are Born, San Diego Scientists Make ‘Amazing Discovery'

Scientists found that neither bird was related to a male. The San Diego Wildlife Alliance said this is the first accounted instance of asexual reproduction to be confirmed in the California condor species

Stock photo of a California Condor
San Diego Zoo Wildlife Alliance

Conservation scientists at the San Diego Zoo Wildlife Alliance reported the first confirmed hatching of two California condor chicks from unfertilized eggs.

The San Diego Zoo Wildlife Alliance said during a routine analysis of biological samples from two California condors in their managed breeding program, scientists confirmed that each condor chick was genetically related to the other respective female condor that laid the egg from which it hatched.

But, scientists found that neither bird was related to a male. The San Diego Wildlife Alliance said this is the first accounted instance of asexual reproduction to be confirmed in the California condor species, and the first in any avian species where the female bird had access to a mate.

“This is truly an amazing discovery,” said Oliver Ryder, Ph.D., Kleberg Endowed Director of Conservation Genetics at San Diego Zoo Wildlife Alliance, who is co-author of the study. “We were not exactly looking for evidence of parthenogenesis, it just hit us in the face. We only confirmed it because of the normal genetic studies we do to prove parentage. Our results showed that both eggs possessed the expected male ZZ sex chromosomes, but all markers were only inherited from their dams [female condor], verifying our findings.”

While this event is well known to biologists, the San Diego Wildlife Alliance said, it is rare in birds and normally observed in females who have no access to males.

Each condor chick, which in this instance are named parthenotes, was produced by two different female condors housed with a fertile male. Each female condor has also produced “numerous offsprings” with their mates, the San Diego Wildlife Alliance said.

“These findings now raise questions about whether this might occur undetected in other species,” Ryder said.

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