Condor Conservation

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Zoo InternQuest is a career exploration program for high school students. Read the Zoo InternQuest Journal and view the Zoo InternQuest Photo Journal.

Perhaps no species illustrates the power of dedication better than the California condor (Gymnogyps californianus).

Listed as endangered in 1967, the condor population was rapidly declining due to habitat destruction, lead poisoning, and poaching. In 1987, the San Diego Zoo and associated partners made the decision to pull the few remaining condors out of the wild in an attempt to save this bird that was on the brink of extinction. While a highly controversial decision at the time, it proved to be a blessing for the condors. Their numbers have increased to nearly 400, half of which have been successfully reintroduced into the wild. But what exactly are the measures taken to ensure their survival?

Intern Dobi prepares to load her sample into the gel.

During our visit to the Beckman Center, we conducted a PCR (Polymerase Chain Reaction) lab test that used condor DNA to determine the sex of a given bird. Unlike some birds, condors do not display sexual dimorphism and thus the males are physically identical to the females. The best way to tell what gender a condor is would be by amplifying one region of its DNA and running it through a gel. Female condors have a heterogametic ZW chromosomal pairing while males have a homogametic pairing: ZZ. Gel electrophoresis is a technique that separates particles of different size and helps us diagnose the presence of the Z and W chromosomes, henceforth determining the bird’s gender.

In addition to sexing the bird, DNA is vital to ensuring that the condor chicks are born healthy. Condors lay only one egg every two years, so it is essential for the survival of the species that the chicks do not have any life-threatening ailments. However, the presence of a certain autosomal recessive allele can prove fatal to a chick if both parents pass the trait down. This allele is responsible for chondrodystrophy, a lethal dwarfism that occurs in 10% of the condor population. Researchers at the Beckman Center work to determine which of the birds is carrying this trait and keep extensive pedigree analyses to ensure that only the most genetically compatible pairs are bred together.

After getting a taste for what measures are taken to help condors in the lab, we headed out to try some hands-on field work that highlighted how researchers are ensuring that released condors are kept safe. Separating into our respective teams, we were given a radio receiver. This hand-held device works by tuning into a certain “radio station” that corresponds to a specific bird. Each released condor is equipped with an identification tag and a small radio transmitter. By setting the tracking device to a specific station, the device can then detect the signals emitted from the transmitter and thus track down the condor. This is very time-consuming work, however. The tracking device emits a series of quiet “beeps” that grow louder and louder as you near the animal. I personally struggled with tracking down a stationary condor in a nearby tree on flat ground within a period of seven minutes. I can only imagine what it must be like to trek the condor’s natural rocky terrain for several hours or days, with the possibility of having to ascend a cliff in search of the roost. Just goes to show the measures the researchers here are taking to ensure that this species will be around for years to come.

Kristina, Conservation Team

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