Interior Secretary Bruce Babbitt released two red-cockaded woodpeckers in a forest Thursday to celebrate a new agreement that's designed to balance protecting an endangered species and developing property.

The "safe harbor agreement" would allow a landowner who protects existing populations of endangered species to develop other land even if new populations are found there.The agreement signed Thursday initially covers landowners with 84,000 acres of South Carolina property.

"What that says is this is an attractive concept for private landowners," Babbitt said.

A similar agreement was signed last week in Texas. Under the program, landowners who have colonies of endangered woodpeckers would have to protect those groups. But they would no longer have to worry that additional colonies could restrict their land use.

"You protect species up front, so later you can do other things on your property," said Cindy Hoffman, a Fish and Wildlife Service spokeswoman in Washington.

Several environmental groups are lukewarm to the idea, however. Both the Sierra Club and Defenders of Wildlife said they will closely monitor what takes place.

"We've never said it's a great thing," the Sierra Club's Dell Isham said. "We would approach this very cautiously. I'm not interested in destroying habitat for endangered species."

The accord covers the red-cockaded woodpecker, a 7-inch bird of which only about 4,500 flocks are known to exist. Found in old-growth forests from Texas to the Carolinas and Virginia, about 700 flocks are in South Carolina.