Wild Condor Egg Is Lost, but It’s Still a Good Sign

A new breeding pair of California condors has established itself among the five remaining birds in the wild, but their first egg had an extraordinarily thin shell and cracked during the weekend, scientists said Monday.

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

“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 an egg had been laid on Wednesday or Thursday of last week, Grantham said.

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 up 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 adult status.

The female and male were seen diving into a steep canyon where they remained for several days, indicating that a nesting cave had been established, he said. The birds are in a remote area of a federally protected condor refuge in Ventura and Kern counties.

Egg Out of Nesting Site

However, scientists discovered the egg had been broken open and was out of the nest when they reached the cave Sunday in an effort to rescue the egg for incubation at the San Diego Wild Animal Park. (By capturing eggs soon after they are laid, scientists have been able to induce breeding pairs to lay again.)

“The eggshell 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 Monday showed the eggshell was 58% thinner than normal condor eggs.

Meretsky said that the female AC-8 could be getting old, since she has bred many times in the past. She has five offspring who were hatched at the Wild Animal Park and are growing up healthy to this point.

“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.

Art Risser, curator of birds at the San Diego Zoological Society, argued Monday that the weekend disclosures buttress arguments by the San Diego and Los Angeles zoos and the federal Fish and Wildlife Service to bring the remaining four males and single female into temporary captivity until a breeding and release program can be undertaken at the two zoos.

The National Audubon Society has obtained a temporary injunction in U.S. District Court in Washington, D.C., 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.

At present, 10 birds are at the Wild Animal Park and 11 at the Los Angeles Zoo.

The remaining birds in captivity are still several years away from maturity.