New Condor Pair’s First Egg Found Cracked in Wild

A new breeding pair of California condors has established itself among the five remaining birds in the wild, but its first egg had a very thin shell that cracked during the weekend, scientists disclosed Monday.

The despair over loss of the egg is tempered by guarded optimism that the pair will breed again in about a month, Jesse Grantham, a National Audubon Society spokesman at the Condor Research Center in Ventura, said Monday.

For more than six years, scientists have been experimenting with ways to save the condor, whose only remaining wild habitat is in a federally protected refuge in Ventura and Kern counties.

The new pair consists of an adult female condor known as AC-8--the only known female left in the wild--and a juvenile male who until now was thought still to be a year away from breeding. The male, IC-9--for immature condor--has been renamed AC-9, signifying his new status as an adult.

“The egg was a very good, very positive sign that we have a new pair,” Grantham said.

Based on visual observations and radio telemetry from transmitters on the birds, scientists suspected that an egg had been laid Wednesday or Thursday, Grantham said. The female and male were seen diving into a steep canyon in the condor refuge, where they remained for several days, indicating that a nesting cave had been established, he said.

Hoping to capture the egg for incubation at the San Diego Wild Animal Park, scientists reached the cave Sunday, only to find that it had been broken open and was out of the nest. (By capturing eggs soon after they are laid, scientists have been able to induce breeding pairs to lay again.)

“The egg shell was extraordinarily thin, even though this female has had a history of laying thin eggs of small size,” Vicky Meretsky, a biologist who participated in the capture attempt, said Monday. “It could have been crushed during incubation, or ravens perhaps might have gotten to it. We don’t know.”

Analysis by the Western Foundation for Vertebrate Zoology showed that the eggshell was 58% thinner than normal.

Meretsky said AC-8 could be getting old, since she has bred many times in the past. She has five healthy offspring that were hatched at the Wild Animal Park.

“Or the other possibility is that there is some sort of chemical contaminant, such as DDT, to cause the thinness,” she said. Biologists plan to carry out a chemical analysis of the shell and remaining egg membrane for organic pesticide residue.

Meretsky said the new pair has exhibited good courtship activity. Scientists hope for another egg after the female recycles, which normally takes 30 days.

The curator of birds at the San Diego Zoological Society said Monday that the egg incident buttresses the case for bringing the remaining four males and single female into temporary captivity until a breeding and release program can be undertaken. The San Diego and Los Angeles zoos and the federal Fish and Wildlife Service have called for such a move.

“If we had done that several months ago, the pair could have gone through courtship and we could have gotten the egg before one of the condors sat on it and crushed it,” Art Risser said.

The Audubon Society has obtained a temporary injunction in U.S. District Court in Washington prohibiting capture of the remaining birds. The society argues that the habitat might not be protected if no birds are left in the wild, and that California condors have not been bred successfully in captivity.

Ten condors are at the Wild Animal Park and 11 at the Los Angeles Zoo. An adult female captured last year has been placed with a male, named Topa-Topa, at the Los Angeles Zoo in hopes that they will reproduce, since Topa-Topa has had no mate in his almost 20 years in captivity.

At the Wild Animal Park, an adult female also from the wild shows affection for a male who is still only 5 years old and considered at least a year away from being able to mate.

The remaining birds in captivity are several years from maturity.