More Condors

Sixteen reintroduced California Condors were captured and treated for lead poisoning in Grand Canyon National Park this summer after five birds were either found or presumed dead from the substance. The incident suggests that the birds may be becoming victims of their own success.
Though scientists could not pinpoint the source of the lead, they suspect the birds fed on an animal carcass full of lead shot—showing that they are increasingly finding their own food sources instead of relying on carcasses left by the recovery team.
Grand Canyon National Park Biologists and The Peregrine Fund's manager for the project in Arizona have observed the birds feeding together and suspects the poisoning could come from a single carcass—although they don't know exactly where the carcass was located because the radio collar signals used to track the condors are interrupted when they fly below the Canyon's rim.
Scientists can only speculate too why the carcass was full of lead shot. Hunting is allowed on some federal lands surrounding the Canyon, but no season was open when the birds began dying in June. Bill Heinrich, species restoration manager for The Peregrine Fund, said that it's possible that some kids may have used a dead animal for target practice or the birds found the carrion on private land.
All of the condors captured in July had lead in their bloodstream. Most were treated with chelate, a substance that binds to the lead and allows the birds to excrete it; a few needed surgery to remove the lead pellets. All six birds have been re-released.
The poisonings are also a concern because they are an indication that the toxic environment could be harming other creatures that are not being monitored. Likely, eagles and turkey vultures could have been affected too.
Getting the condors to forage on their own has been one challenge of the program, which began in 1996 as a cooperative effort by The Peregrine Fund, the us Fish and Wildlife Service, the Arizona Game and Fish Department, the National Park Service and Bureau of Land Management (blm). The first captive-reared birds were released at Vermilion Cliffs, Arizona, blm land north of the Grand Canyon. Each year, about a dozen birds are released in this area, and to train the young birds to forage, carcasses are left out by the recovery team. Some of the older condors, however, are now showing a preference for dead bighorn sheep, deer, and elk in the park.

In addition to continuing to provide a healthy source of food for the young birds, the recovery team also aims to persuade local hunters to use nontoxic bullet alternatives as they become available. One such “green” bullet, a composite of tungsten, tin, and bismuth (ttb), is being considered for use by the military to reduce contamination on its training grounds.
While foraging skills improve among the birds at the Grand Canyon, high mortality and the condor's inquisitive nature create other obstacles for recovery. In the wild, a baby condor stays with its parents for the first year, learning to feed and avoid dangers. The released birds are juveniles that must fend for themselves. Some are killed by golden eagles and coyotes while competing for food; others have flown into power lines or ingested antifreeze.
Because condors cannot smell, the bird's curious nature evolved to help them find food by following visual cues from other animals, such as ravens or eagles. The reintroduced condors have shown up in campsites, parking lots, and picnic areas. They have shown up in some fishermen's sites and backpackers camps and dragged away firewood, tents and other camping equipment.
Inside the park, people have put children next to the birds for a photo or walked up to them for a close view, not behavior that the park recommends. It's a wonderful experience to see one of them, and we want people to know that the Endangered Species Act works. But we also want people to see them in their natural, wild state. This means keeping people at a distance so the birds are not habituated.
If the juvenile birds learn to avoid the dangers of human interaction and competitive species, they have a good chance of reaching sexual maturity. The first condors released—now about six years old—are reaching that stage and beginning to show signs of pair bonding. The team hopes to see wild birds born in the next three to four years. As of July, 48 California condors lived in the wild in Arizona and California, and 123 were in captive breeding facilities. Thirteen more condors are scheduled to be released in the Grand Canyon vicinity in December.
Elaine Leslie