Key among issues are lead poisoning caused by condors eating animals, or gut piles from animals, shot with lead ammunition. Wind turbines being planted along ridgetops near condors' ranges pose an increasing threat.
Good news for California condors: Their population just topped 400 – 405 to be precise – the most since the effort to save the species began 30 years ago as it teetered on extinction’s edge.
An April 30 count found 226 of the enormous vultures flying free over California, Arizona and Baja, Mexico, and 179 living in zoos and four breeding centers, including the Jonsson Center for Wildlife Conservation, an Oregon Zoo-run operation in rural Clackamas County.
That said, the species faces steep challenges, and the Oregon Zoo program, which has hatched 35 chicks altogether, has had a tough spring.
Among eight eggs laid, three chicks have survived with one more due to hatch around June 9. One egg was infertile. One contained an air bubble that destroyed vesseling, so the embryo died. Two other late-stage chicks died despite efforts by zoo staff to help them hatch; the veterinarian sent tissue samples to a lab to try to determine what went wrong.
“We know their yolk sacs looked odd. They were enlarged,” said Kelli Walker, senior condor keeper. “But nothing on the necropsy was obvious.”
For Walker and others working in the condor recovery trenches, each loss disappoints and each new chick is a precious addition to a species that once symbolized American wilderness. California condors used to range across much of the nation; explorers Lewis and Clark dubbed them the “beautiful buzzards of the Columbia.”
But the bald-headed birds whose wings span nearly 10 feet and who can live up to 60 years were almost wiped out by 1982, when only 23 remained in the world.
Five years later, the U.S. Fish and Wildlife Service and partners captured the remaining wild condors and placed them in breeding programs at the Los Angeles Zoo and San Diego Zoo Safari Park. The Peregrine Fund’s World Center for Birds of Prey in Boise established the third breeding center, and the Oregon Zoo built its condor barn and flight pens in 2003, welcoming its first breeding pairs that November.
It was believed to be the first time in nearly 100 years the birds had spread their wings in Oregon, part of their historic range.
Including the new chicks, the zoo houses 46 condors today.
Of the chicks hatched in Oregon, 21 have been released in California and Arizona; Oregon has no release sites. Five of those since have died. It’s suspected, Walker says, that lead poisoning killed three. One was caught by a mountain lion. Cause of death for the fifth bird is unknown.
Other surviving Oregon Zoo-hatched condors have been kept for breeding because of their genetic value to the species.
Hitting that 400-bird mark isn’t necessarily scientifically significant, but it bolsters the spirits of those working to revive a species that plays a key role in nature. Condors feed only off dead animals, picking them clean, which helps keep disease from spreading.
A more momentous number, if it comes, will be 450.
When wildlife officials, conservationists and others drafted a recovery plan for the species in 1996, they determined that until there were at least 450 condors, they couldn’t be considered for delisting under the U.S. Endangered Species Act.
Plus, that magic number comes with strings. According to the plan, condors need to be dispersed among three 150-bird populations – two wild and one captive, with 15 breeding pairs in each group. And they have to be self-sustaining, reproducing and expanding on their own.
“We’re not there yet,” says John McCamman, who took over in March as California condor coordinator for USFWS.
For as much progress as the program’s made, McCamman says, it faces serious challenges that will help guide an upcoming re-write of the recovery plan.
Key among issues are lead poisoning caused by condors eating animals, or gut piles from animals, shot with lead ammunition.
Wind turbines being planted along ridgetops near condors’ ranges pose an increasing threat.
Along the California coast near Big Sur, a condor release site, biologists have noticed serious eggshell thinning. They believe it results from condors feeding on sea lion carcasses containing DDE, a residual from the now banned insecticide DDT. DDE remains in the water column off California, where lots of the insecticide was dumped.
As they re-draw the recovery plan, McCamman says, scientists and other condor caretakers will look at those issues and more – everything from habitat loss to the potential effects of climate change on condors’ ability to survive. They’ll talk about whether to open a fifth breeding center at Mexico City’s Chapultepec Zoo, or develop another release site, perhaps in the Siskiyou Range, near the California-Oregon border.
The process is likely to take years and include input from lots of parties.
“The one thing about condors,” McCamman says, “is they’re loved by everybody. Lots of institutions and organizations are interested in their long-term survival.
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