Endangered, Condor Birds Can Reproduce Without Mating

California Condor. (Wikimedia Commons/Joe Parks)

JAKARTA - California condors, an endangered species, can breed without mating, according to a study by conservation scientists at the San Diego Zoo Wildlife Alliance in the United States.

During routine analysis of biological samples from California condors in the zoo's breeding program, scientists discovered two condor chicks had hatched from unfertilized eggs.

"To be honest, this was a huge surprise. We didn't expect to find all this," said Cynthia Steiner, associate director for the alliance's conservation research division.

Steiner is also a co-author of a study published last week in the 'Journal of Heredity', the official publication of the American Genetic Association.

Scientists confirm that each condor chick is genetically related to its mother. However, none of the birds are genetically related to males.

The two birds represent the first two confirmed examples of asexual reproduction, or parthenogenesis, in the Californian condor species, the zoo said.

"This is a very rare find, because it is not known in birds in general. So, it is known in other species, in reptiles and in fish, but in birds very rarely, especially in wild species," said Steiner.

Steiner said the discovery was particularly surprising, as the two female birds were constantly placed with fertile male partners and had produced offspring when paired with males.

California condor. (Wikimedia Commons/Don Graham)

Asexual reproduction has not been previously confirmed in any bird species, where the female has access to a mate.

"At some point they decided, for some reason, to do asexual reproduction as well," explains Steiner.

Both chicks were underweight when they hatched, Steiner said. One was released into the wild and died at the age of two in 2003, while the other survived eight years in captivity and died in 2017.

The California condor is one of the rarest bird species in the world, but its population is steadily increasing. Steiner said there are now about 500 condors alive, about 200 in captivity and 300 in the wild.

He hopes to continue studying asexual reproduction in condors, to see if that continues now, as there are more condors in the wild.

"We just wanted to know how often this phenomenon might occur now that the population is growing, rather than shrinking like it was in the 1980s."