Officials at Valley Forge National Historical Park say deer will be shot there starting next month, ending a yearlong delay and commencing a controversial plan to dramatically thin the herd.

An animal-rights group responded to Monday's announcement with an immediate pledge to demonstrate at the park. And an attorney said he might seek a restraining order to try to stop the shooting.

A year after putting off a scheduled November 2009 deer kill, Valley Forge Park officials said Monday that they were going forward with "lethal reduction."

They said the goal is to reduce a herd that has grown large and destructive, gobbling so many plants that the forest cannot regenerate. Four years of annual shoots are planned to eliminate 86 percent of the herd, from an estimated 1,277 deer to between 165 and 185.

Each year's shoot will begin in November and end in March. Park officials said they would not announce specific dates in advance.

Sharpshooters are to kill 500 deer this winter, 500 the next, and between 250 and 300 each in the third and fourth years. The plan is for federal employees or contractors to fire silencer-equipped rifles, mostly at night, at deer lured to baited areas. After the four-year hunt, officials plan to maintain the smaller herd through contraceptives and additional shooting.

"We waited our year," park spokeswoman Kristina Heister said Monday. "And now, we're going ahead."

Park managers estimate that shooting deer will cost between $2.0 million and $2.9 million during the next 15 years.

Animal-rights activists say the killings are harmful, unnecessary, and dangerous to people who live or travel near the park.

"It's risking human life and injury," said Elizabeth Madden of Keep Valley Forge Safe. "It's a gamble a sane society should reject."

For the deer, Valley Forge Park is a 5.3-square-mile forest sanctuary, albeit one surrounded by houses, hotels, and the King of Prussia mall. The park draws more than one million visitors a year, from local communities in Montgomery and Chester Counties, and from cities across the nation, though at times it can seem as if deer outnumber people.

A lawsuit filed last year by the Friends of Animals, a national advocacy group, and Compassion for Animals - Respect the Environment (CARE), a West Chester organization, stopped the 2009 shoot. Park officials said at the time that their desire to evaluate related contracts also delayed its start.

The lawsuit said that deploying sharpshooters in winter, the season when Gen. George Washington's troops suffered at Valley Forge, was "an appalling twist on the park's history" and "another sign that the National Park Service has abandoned its century-old mission to strive for parks in which conservation of nature is paramount."

Park Superintendent Michael Caldwell said Monday that the deer-driven degradation at the park made it imperative to proceed.

"We believe the best course is to go forward at this point," he said. "We'll await the legal process as it unfolds."

Caldwell said that he respected the court, but that the longer the shoot was delayed, the more deterioration would occur in the park. He estimated that if the shootings take place as scheduled, vegetation will still need five to 10 years to recover.

There's little debate that the lack of natural predators and public hunting, combined with an ideal habitat, have spawned a huge expansion in deer.

In communities across the region, officials have turned to firearms as a solution. In Philadelphia, the Fairmount Park Commission shot deer for several years. Last year, Lower Merion officials undertook a series of shoots to kill 576 deer they said were responsible for environmental damage, car wrecks, and Lyme disease.

Still, the plan to kill deer at Valley Forge has provoked enormous dispute. Some people see deer as peaceful creatures that are a welcome part of the scenery. Others see them as nuisances that devour neighborhood gardens and run onto highways.

On Monday, Matt McLaughlin, director of the Pennsylvania chapter of Friends of Animals, said the group remained "adamantly opposed to what the park was doing. We'll be out at Valley Forge Park to demonstrate."

It was unclear Monday night when those demonstrations might occur. The group held vigils at the park last year, in advance of the shoot that was put off.

Michael Harris, who prepared the lawsuit as director of the Environmental Law Clinic at the University of Denver, planned to talk with his clients about seeking an injunction or temporary restraining order. He hoped to speak with park managers to see if further delay would be acceptable, he added.

"When they entered into the 'standstill' agreement last year, part of it was to give the plaintiffs an opportunity for their day in court," Harris said. "I'm a little disappointed that had a time limit on it. The deer did not get their chance to go to court."

The case is still active in U.S. District Court in Philadelphia, although it is unclear when a ruling might come.