First Oregon Zoo condor released to wild is also sitting on an egg
California condors are laying the groundwork for species recovery one egg at a time.
The first three eggs of the 2013 breeding season arrived at the Oregon Zoo's Jonsson Center for Wildlife Conservation over the past week. Malibu laid the first egg Feb. 14, Ojai laid the second yesterday afternoon, and Squapuni laid the third this morning.
"Each new egg is critical to the California condor's comeback," said Kelli Walker, the zoo's lead condor keeper.
The birds and their mates — Maluk, Atishwin and condor No. 189, respectively — will sit on the eggs for up to two weeks before keepers remove them to check whether they are fertile.
This determination is made through a process called candling — using a bright light source behind the egg to show details through the shell. Fertile eggs are placed in an incubator to prevent any potential damage, and the condor parents will sit on dummy eggs until hatching begins, usually in 54 to 58 days. At that time, Walker switches the real eggs back, so that the chicks can hatch under their parents. The conservation center should see its first chick of the season in early April.
Walker said the first condor eggs came a little later than usual this year — they typically arrive in early February. She monitors the birds via closed-circuit cameras in their nest-boxes, and had seen signs that the eggs were coming.
"Usually, a bird that's about to lay an egg won't leave the nest room for about 24 hours beforehand," Walker said. "She'll spend a lot of time in the corner, and she'll start to look pretty uncomfortable right before she lays it."
Once an egg has been laid, Walker removes it at the first opportunity, quickly weighing it and making sure the shell is in goodcondition before replacing it in the nest box. Malibu's egg weighed just shy of 11 ounces and looked to be in fine shape, Walker said. She planned to check Ojai's and Squapuni's eggs today.
Walker expects three or four more eggs will be laid this year.
In related news, Kun-wak-shun — the first Oregon Zoo-hatched condor to be released into the wild — has paired with a wild-fledged female in California's Pinnacles National Monument this year and the two are now taking turns sitting on her egg. Kun-wak-shun hatched at the Jonsson Center in 2004 and took to the open skies in 2005, joining other wild condor residents in the 26,000-acre national park. On three occasions since, he has been removed to the Los Angeles Zoo for chelation therapy to remove lead from his system.
Accumulated lead poisoning — a problem that plagues all raptors and scavengers — is the most severe obstacle to the California condor's recovery as a species. As the birds feed on carrion and other animal carcasses, they can unintentionally ingest lead from bullet fragments. Leadconsumption causes paralysis of the digestive tract and results in a slow death by starvation. Lead also causes severe neurological problems, so the birds not only starve but suffer from impaired motor functions.
The California condor is classified as a critically endangered species. In 1982, only 22 individuals remained in the wild. With the help of breeding programs like the Oregon Zoo's, condor numbers now total around 400, counting those in breeding programs and in the wild.
More than 30 healthy chicks have hatched at the Jonsson Center since the program began in 2003, and 23 Oregon Zoo-reared birds have gone out to field pens, with most released to the wild. In addition, several eggs laid by Oregon Zoo condors have been placed in wild nests to hatch.
Condors are the largest land birds in North America with wingspans of up to 10 feet and an average weight of 18 to 25 pounds. They are highly intelligent and inquisitive, and they require a tremendous amount of parental investment in the wild.
The California condor had a long history in Oregon. Lewis and Clark saw the large birds as they traveled along the Columbia River. Local archaeologists have unearthed 9,000-year-old condor bones from NativeAmerican middens, and condors were a common motif for the designs of Oregon's Wasco people, who lived along the Columbia River between The Dalles and Cascade Locks. The "Thunderbird" was considered a spiritual guide to the native peoples and is a key character in many myths.
The last condor seen in Oregon was near the town of Drain in 1904. The birds held out a little longer in California, but by 1987, the last condors were taken into captivity in an attempt to save the species. Biologists decided to place the remaining condors in a captive-breeding program. The California condor was one of the original animals included on the 1973 Endangered Species Act.
The Oregon Zoo's condor recovery efforts take place at the Jonsson Center for Wildlife Conservation, located in rural Clackamas County on Metro-owned open land. The remoteness of the facility minimizes the exposure of young condors to people, increasing the chances for captive-hatched birds to survive and breed in the wild. A new California condor habitat will open at the zoo later this year, allowing visitors to get a look at nonreleasable condors and learn more about these iconic birds.
California condor breeding programs are also operated at San Diego Zoo's Wild Animal Park, the Los Angeles Zoo and the Peregrine Fund's World Center for Birds of Prey in Idaho. The Oregon Zoo received The Wildlife Society's conservation award in 2005 for "creating the nation's fourth California condor breeding facility."
Learn more about the Oregon Zoo's California condor recovery program.