Condors without Borders

I am looking through a tiny porthole through which I can see 13 young California condors in a socialization pen (photo 1). This is a one-way mirror, so the condors cannot see me, but I can see them. They are sitting on manmade wooden perches in a large netted enclosure full of half-eaten carcasses (photo 2). 

Condors are obligate scavengers meaning they fly in search of deceased animals or carrion. They serve as a very important cleanup crew, and without scavengers like condors, the world would be a dirtier place. Condors are not necessarily picky; they have been known to feed on small carcasses of ground squirrels and larger animals like deer, cattle and even beached whales!

In the 1980s, the California condor population had drastically declined and the remaining 22 wild condors were brought into a condor captive breeding program for a total of 27 birds. Today due to intensive conservation efforts the population has rebounded to over 460 condors with more than 300 flying free in the wild!

The condors I am silently watching hatched about a year and a half ago and have spent their lives at the Peregrine Fund’s World Center for Birds of Prey (WCBP). The San Diego Zoo (SDZ) and WCBP have played an important role in condor captive breeding. WCBP has 20 breeding pairs of birds, whose chicks are hatched and reared for release at field sites in the western United States. Many efforts are taken to ensure these chicks are strong candidates for release when the time is right.

Chicks at the WCBP are parent reared and if there are no complications, chicks are hatched and raised in a flight pen with their parents and rarely, if ever, see a human. The nest box is on top of a platform in the flight pen to initiate the chicks to fledge, this usually happens around 6 months of age. 

After fledging in the wild, the parents are not off the hook yet, as the chick will stay with its parents for a year or more while learning how to be a condor. This intensive parenting is a huge challenge for the successful recovery of this species since adult condor pairs only produce one egg every other year. 

We were at the WCBP for the annual California Condor Field Team Meeting. This meeting brings together field crew members, scientists, zookeepers and veterinarians to discuss the future management of the California condor flocks. These young condors, in particular, are going to join flocks of condors in the wild to be a part of a major reintroduction effort. 

Intensive captive breeding efforts are still necessary while we continue to grow the wild condor population. While birds in the wild are producing chicks, there are still many threats to their survival. In terrestrial landscapes, condors are exposed to lethal amounts of lead found in nonprofferred carcasses. Lead is still the largest threat to the recovery of this species with half of all condor deaths due to lead poisoning.

In coastal habitats, condors feed on marine mammals washed ashore and are exposed to high levels of endocrine-disrupting chemicals (EDCs). While long-term effects of these EDCs on condors is still not known, we do know that exposure can interfere with condor endocrine function and ultimately reproduction. Mitigation of terrestrial and aquatic threats is necessary to have a self-sustaining, free-flying California condor population in the future. 

In Reproductive Sciences we are interested in understanding how EDCs found in the California condor’s environment effect reproduction. We share and discuss our finding with the field team at the annual meetings. One day I hope our work will help shape management decisions that will ultimately increase condor chicks survival in the wild moving these birds toward a more stable, wild population less reliant on chicks hatched in captivity. 

See other California condor blogs from the Reproductive Sciences lab:

https://institute.sandiegozoo.org/science-blog/seafood-condors

https://institute.sandiegozoo.org/science-blog/california-condor-field-trip

https://institute.sandiegozoo.org/science-blog/research-opportunity-lifetime

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