"The peregrine is making a great recovery in several areas of the United States," Walton said. "But we still have the pesticide problem in many areas."
If the bird is to be down-listed, it could cost the Peregrine Fund its federal funding. Burnham said the center would try to carry on, without its most glamorous bird.
"When the Peregrine Fund was created, there was no intention of us existing beyond recovery of the peregrine falcon," Burnham said. "There are a limited amount of resources that now need to be directed toward other species that need it."
A major "Maya Project" is under way to study tropical raptors in Guatemala and Belize. Peregrine Fund biologist Willard Heck spends much of every year on the island of Mauritius off the east coast of Africa, working to save the rare Mauritius kestrel.
Those and more than 40 other troubled species have been brought to Boise for study and breeding in buildings apart from the peregrines. There are malevolent looking black African eagles, American bald eagles, golden eagles, elf owls and Fiji and aplomado falcons. The facility conducts about 3,000 people through on tours each year.
The peregrines are isolated in a shed similar to a cellblock. They flash their lethal talons as they swoop to the barred windows in the doors. They eyeball strangers fiercely.
Especially during nesting time, scientists such as Heck and Cal Sandfort, the technical associate for raptor propagation, put in long hours for low salaries, watching over the various species via an array of TV monitors and through slits in doors.
Although some claim the Peregrine Fund has ulterior motives to down-list the bird, Heck differs.
"That's the way the Endangered Species Act works," he says. "A lot of protectionists are using the act to protect things in many directions. For example, to use the spotted owl to protect an old-growth forest, in my mind, is not the way it was meant to work.
"You put things on (the list) when it's needed, but you're also obligated to take things off when it's not needed."
The Peregrine Fund continues to release 200-300 birds a year.
Burnham said: "There's no way in the world everybody's going to like us. But when you look at the whole record, it's pretty good."