Parthenogenesis in California condors

If you’re an avid birder, like me, or even just a general bird enthusiast, you have probably heard of the California condor. As the largest living North American land bird, it is the only surviving member of the Gymnogyps genus of New World Vultures. While we do not have California condors here at the Zoo, we do have other vulture species, including one New World vulture species, the king vulture.

California condors have specifically been the subject of study since 1980, when scientists captured the remaining 27 wild birds and created a captive breeding program to restore wild populations. There are now over 500 in zoological settings, and wild populations are on the rise (although they are still considered critically endangered).

Switch gears with me very quickly, and I am going to introduce another concept that is important to this blog post. If you’re not a biologist, you may not know what the term parthenogenesis means. To put it simply; parthenogenesis is a mode of asexual reproduction in which young develop only from a female egg, without fertilization from a male of the same species. It is a phenomenon observed often in reptiles/amphibians and has also been witnessed in some fish species. It is nowhere near common in avian species — there have been parthenogenically fertile eggs observed in domestic poultry, for example, but it is exceedingly rare and not often successful.

Now here is the breaking news that brings these two pieces of information that I just shared with you together. In 2021, scientists discovered the first instance of successful facultative parthenogenesis in California condors! After extensive genetic testing, scientists determined that two chicks born in 2001 and 2009 had no evidence of male paternity and were completely genetically related to only their mothers. I know you read this and thought: “That sounds awesome. But why does it matter?” Great question! The answer is a lot of reasons. Firstly, this is one of the first observations of successful facultative parthenogenesis in an avian species. Secondly, it was in a California condor! A critically endangered scavenger that is potentially a very important part of an ecosystem. Not only does this prove a case for how closely birds may have been related to dinosaurs (as I mentioned, parthenogenesis is a common phenomenon among them), but it provides an optimistic outlook on the fate of the California condor. With endless anthropogenic effects on the world’s ecosystems, endangered species often have an uncertain future. And whether you had all this knowledge before reading this Keeper Stories blog, or you learned many new words today, you can go home today knowing there is a beacon of hope for the California condors. I encourage everyone to read up on how incredible they are!

Robin D.
Seasonal Keeper, Birds