When our released California condors nested in Baja California, Mexico, for the first time, San Diego Zoo Global wildlife biologist Mike Wallace, Ph.D., feared the precious egg might be infertile. To ensure the parents had an opportunity to raise a chick, he worked through the U.S. and Mexican permitting process to take an egg from the San Diego Zoo Safari Park’s breeding program and switch it with the wild egg in the nest. Carefully cradling the replacement egg in his pack, he rappelled down a steep cliff to reach the nest on a ledge. When he arrived at the nest, he surprised the mother condor. “She came at me,” he said, “and when I looked up into the nest, instead of an egg, there was a chick!” It was a milestone to celebrate: the first successful wild hatching of a California condor in Baja California in more than 30 years.
San Diego Zoo Global is a leading partner in the efforts to save the California condor. In 1982, only 22 birds remained in the wild, and the species was in imminent danger of extinction. If California condors were to survive, steps needed to be taken to bring the remaining birds into a safe environment and begin a breeding program to try to build the population. We were given permission to begin the first zoological propagation program for California condors, in cooperation with the U.S. Fish and Wildlife Service, California Department of Fish and Game, the National Audubon Society, and the Los Angeles Zoo.
It took a variety of techniques developed by scientists and bird keepers to do this. Eggs were removed from condor nests, encouraging the females to lay replacement eggs. This is called “double clutching.” The removed eggs were placed in incubators for hatching. To reduce imprinting on humans, the hand-raised condors were fed and cared for using adult look-alike condor puppets. Taped sounds were played to the chicks as well during the hatching process. In the wild, both parents incubate the egg and care for the chick, and they may only raise one chick every other year. Using the double-clutching method, we can raise up to four chicks in a two-year period.
In 1992, the first zoo-bred condors were released into the wild in California. As of April 30, 2013, the population of California condors had grown to 417, including 240 condors living in the wild. Reintroduction is not the end of the story, however. Appreciation and protection of the condors’ wild habitat is crucial for their ongoing survival, as is a continued breeding program, and San Diego Zoo Global has an ongoing commitment to keep California condors soaring in the skies.