National Park Service officials have called off this winter's long-planned and highly controversial deer kill at Valley Forge National Historical Park.

Park Superintendent Michael Caldwell confirmed yesterday that the planned shooting of 500 deer would not go forward, as officials evaluate contractual matters and a pending lawsuit by two animal-rights groups.

"We're still committed to implementing the plan," Caldwell said. "If we don't have [it] this year, then we'll begin when we can."

Yesterday, it was unclear when that might be.

A federal judge is not scheduled to rule on the legality of the plan before May 31. That means, as confirmed to the Associated Press by Assistant U.S. Attorney Richard Bernstein, that the first deer kill could not occur until next November at the earliest.

And there were signs that other groups may be planning additional legal action to stop deer from being shot.

"It's a victory," said Michael Harris, who prepared the animal-rights suit as director of the Environmental Law Clinic at the University of Denver. "They were going to go out and commence this hunt this winter, and [now] we've got our opportunity to have this decided."

The Friends of Animals, a co-plaintiff, is pleased the deer have a "holiday reprieve," Harris said. He added the group "will continue to fight on their behalf until this illegal plan is fully set aside."

The plan called for sharpshooters to eliminate at least 1,500 deer in four years - 500 this winter, 500 the next, and between 250 and 300 each in the third and fourth years. That would eradicate 86 percent of a herd that park officials say has grown big and destructive.

Caldwell gave two reasons for the postponement. First, the November-to-March window for conducting the shoot was fast closing, and the park won't be able to award a sharpshooting contract before next year, he said. At the same time, he said, the park is determining how to proceed with the lawsuit.

The superintendent declined to comment on the litigation. Friends of Animals and a second group, Compassion for Animals, Respect the Environment, of West Chester, filed suit last month against Caldwell and other park service officials to stop the kill.

Animal advocates met yesterday's news with delight.

"I think the longer we can delay it and the more information we can get out, the better," said Betty Madden of Keep Valley Forge Safe, which maintains that gunfire could injure people living or traveling near the park. "There's a lot of flawed information in the plan itself. We need a new public hearing."

Caldwell has expressed full confidence in the science behind the plan, its safety provisions, and the hearing process that led to its adoption. The park maintains that deer eat so many plants and saplings that the forest cannot regenerate.

The lawsuit claims that the park study that blamed deer for ruined vegetation was flawed and that the law requires administrators to protect natural resources, including deer.

The plan to kill deer at Valley Forge has provoked enormous controversy. Some see deer as a welcome part of the park scenery. Others see them as four-legged nuisances that devour neighborhood gardens and run into backyards and onto highways, putting people and cars in danger.

The lack of natural predators and public hunting, combined with an ideal habitat, have spawned an exponential expansion among deer. In 1985, the deer population was estimated at 165 to 185. The herd peaked at 1,398 in 2003, according to park officials, and now has about 1,275 deer. Officials want to reduce the herd to 1985 levels.

The plan was for federal employees or contractors to fire silencer-equipped rifles, mostly at night, at deer lured to areas baited with apples and grain. After four years of this, officials said, the smaller herd could be maintained through contraceptives and further shoots.

Caldwell, asked if canceling this winter's shoot meant that the four-year plan would simply be pushed forward or perhaps revaluated, said, "We'll always evaluate the progress of the plan." Beyond that, "pending the litigation, it would just be best not to comment."

Contact staff writer Jeff Gammage at 215-854-2415 or jgammage@phillynews.com.