With the deer herd still above target levels, and other methods of control - including contraception - deemed unsuitable, federal sharpshooters are returning to Valley Forge National Historical Park for a fifth season.

To the chagrin of some animal-rights activists, the herd has been reduced by about 80 percent since the culling operation began, the park says - from 1,227 in 2009, or 241 deer per square mile, to about 250, 49 per square mile.

The park says the comeback of some of the vegetation that had been decimated by the deer population speaks to the merits of the program but adds that more culling is necessary for the sake of the plant life.

"Some of the criteria are not there yet, but we're definitely improving," said Kate Jensen, the park's acting natural resources manager.

"It's been good for the park," said Bruce Davis, who lives on Weedon Road near the park boundary. "You can see the difference now when you drive through."

And, he said, it's been good for the neighborhood.

"We don't come home to 10 deer in the yard," he said. "You don't see the deer darting into traffic."

But another neighborhood resident, Jeffrey Houdret, wonders if Valley Forge has gone too far.

"They really have annihilated the herd," Houdret said.

Lee Hall, who represented animal-rights groups in an unsuccessful lawsuit against the park, said Valley Forge should not be in the deer-slaying business.

"The park's focus is history-telling, and we understood, given that the deer weren't eating George Washington's headquarters, they'd always have a safe refuge," Hall said.

In July 2012 the park said that the program "will take up to four years." However, the park has not settled on an acceptable alternative control method, so a fifth season is underway.

Annually, the seasons begin on unspecified dates between November and March. U.S. Department of Agriculture sharpshooters kill the deer, which are lured to a certain area.

Ultimately, the park wants the population down to 30 to 35 deer per square mile, said Deidre Gibson, chief of resources for Valley Forge.

According to monitoring by the National Park Service, overgrazing by white-tailed deer has disrupted the growth of tree and shrub seedlings in the park.

Bucks can eat four to six pounds of food a day and can weigh up to 300 pounds.

Gibson said Valley Forge has kept abreast of deer-control alternatives, such as contraceptives.

But she said they have not met park standards, which include limited behavioral impacts on the deer and no hormonal residue in deer meat, which is donated to food banks.

Allen Rutberg, director for the Center for Animals and Public Policy at Tufts University, has been working with a vaccine for deer contraception since the early 1990s, and said the criteria appear "somewhat arbitrary."

Rutberg said that deer can be captured or darted with the vaccine, and that he is currently working on new darting technology that will allow users to dart deer at further distances. He said contraception might not cost that much more than culling, and the public likely would find contraception preferable to killing.

He noted that for 20 years, the Park Service has used contraception to control horse populations, as it has done at Assateague National Seashore in Maryland.

For Houdret, culling represents a "radical step" to control the deer population. He said that over the years, he has witnessed tourists take pictures of the deer in Valley Forge, but that that is not possible anymore, since he doesn't see deer anymore.

"When they started the culling, there were deer everywhere," Houdret said. "Now, I just don't know where they're going to find these deer to cull."