Breeding season is well underway at the San Diego Zoo Safari Park’s California Condor Breeding Facility!
Since 2012, it has been our pleasure to show you the live nesting activities of a California condor pair on San Diego Zoo Global’s Condor Cam. As our longtime viewers know, for most of those years, the pair that nested online was our very experienced duo, male Sisquoc and female Shatash. Although they are still paired together and preparing to hatch their egg from this season, we will be presenting a new pair for viewing. The male is named Siwon (pronounced “SEE-won”) and the female is named Sola (pronounced “SO-lah”).
Siwon hatched at the San Diego Zoo Safari Park in 1993. In 1997, he moved to the Peregrine Fund’s World Center for Birds of Prey in Boise, Idaho. Once he matured, he joined the breeding population and was paired with a female named Haku. Together they produced 9 chicks. In 2014, it was decided to send him back to the Safari Park to be paired with a new female, Sola. You can identify Siwon by his blue wing tags, which read 85; Sola does not have any wing tags.
Sola also hatched at the Safari Park, but in 2008. She moved to the San Diego Zoo in 2009 to be part of the first group of condors to live in the new Elephant Odyssey habitat. In 2012, she moved back to the Safari Park to live in Condor Ridge. Two years later, she was introduced to Siwon.
This will be their fifth breeding season together. They have already produced two chicks, and they parent-reared both of them, one each in 2017 and 2018.
Usually, Condor Cam starts up a little earlier in the year. This year has had a bit of a delay because we were waiting for Siwon and Sola to double-clutch, or lay a second egg for the season. Birds, depending on the species, lay a certain number of eggs to complete their nest; bald eagles lay 2, bluebirds lay 4, and mallards lay 10-12. Condors lay just one egg in a nest. This small clutch size results in a very slow hatch rate. When their mortality rate was artificially increased by humans through lead poisoning or shooting, this low hatch rate was not sustainable, causing them to become critically endangered. In 1982, there were just 22 California condors left on Earth.
In an effort to quickly increase the population, it was discovered that if we removed the egg from the nest, simulating an egg loss, the pair would likely lay a replacement egg 28-32 days later, effectively doubling that pair’s breeding effort for the year. In some cases, we have been able to get a pair to triple-clutch, if necessary. This process, called multiple-clutching, is an important tool used to help conserve condors.
Geneticists for the Recovery Program recommended that we try to double-clutch Siwon and Sola for this season. They produced their first egg on 29 Jan 2019 and Sola recycled to lay her second egg on 19 Mar 2019. The first egg was sent to the Oregon Zoo, one of our valuable partners in the Recovery Program, to be foster-reared by a condor pair whose egg was infertile. If all goes well, the second egg will be raised by Siwon and Sola on Condor Cam.
Stay tuned for future blogs with egg updates. If you have any questions about what you’re seeing, feel free to ask them in the “Comments” section at the end of this post, and we’ll do our best to provide answers. Happy viewing!
Ron Webb is a senior keeper at the San Diego Zoo Safari Park. Read his previous blog, Moving Day for Kitwon.