10 November 2021

Sometimes DNA tests reveal more than anyone thought possible.

In 1987 when California condors (Gymnogyps californianus) were close to extinction the California Condor Recovery Plan established a captive breeding program that resulted in 518 condors in the wild as of 2019. Built into the program are routine DNA tests of condor offspring to make sure they will not be inbred. When scientists in San Diego performed paternal analysis of two recent captive offspring they were in for a surprise. The two had no fathers even though male condors were present. The mothers hatched viable eggs without mating. Were they Virgin Mary Vultures?

Well, not really. In Christian and Muslim theology the Virgin Mary conceived Jesus through the Holy Spirit while still a virgin. These mother condors used asexual reproduction, parthenogenesis, to produce viable youngsters.

As Wikipedia explains, parthenogenesis occurs naturally in some plants, some invertebrate animals, and a few vertebrates including some fish, amphibians, reptiles and very rarely birds. But not in mammals. There are no known cases of naturally occurring mammalian parthenogenesis in the wild. If it happened the offspring would be female.

Parthenogenesis is incredibly rare in birds. KPBS describes how they found it in San Diego.

Does asexual reproduction ever happen among wild birds? We will never know.

Learn more about Parthenogenesis here. Read the published study at Facultative Parthenogenesis in California Condors.

(photos from Wikimedia Commons, video embedded from KPBS)