Earth Notes: Condor Parthenogenesis
California condors don’t have an easy time raising their chicks. The eggs take two months to hatch, and it’s a full year before the baby birds can live on their own. But now scientists know condor mothers can skip a step in the baby-making process if they want to. They don’t have to mate with a male to lay a healthy egg.
Scientists with the San Diego Zoo Wildlife Alliance did extensive genetic testing on condors in captivity and unearthed a surprise. Two eggs had hatched into babies that didn’t have any genetic material from a father.
This form of asexual reproduction is called parthenogenesis. It’s common in nature in a wide range of species, from sharks to snakes to starfish. But it’s rare in birds and scientists thought it only occurred when the mother couldn’t find a suitable mate. That wasn’t the case here. Both the female condors had mated before and still had access to a male. It’s a mystery why they chose to skip mating and go straight to egg-laying. The resulting baby chicks are referred to as “parthenotes.”
As a species, California condors are imperiled by lead poisoning and other human-created threats. Only about three hundred condors live in the wild. With ten-foot wingspans, the birds look primeval as they soar over the Grand Canyon or the rock pinnacles of southern Utah. Their numbers are rebounding thanks to a captive breeding and release program. The parthenote chicks offer hope for a species that is endlessly innovative in its struggle to survive.