The deer population at Valley Forge National Historical Park evidently isn't what it used to be; in fact, at last count it was less than a third of what it was a few years ago.

Federal sharpshooters have killed close to 1,000 deer since a culling program began in late 2010, according to the National Park Service.

While animal-rights activists have opposed the four-year "lethal reduction" plan, and have fought it unsuccessfully in the courts, the park service says the Valley Forge forests are fighting for their lives and that some of the plant life already appears to be responding favorably to the thinning of the herd.

"Park forest may already be showing signs of recovery," the agency said in a news release Monday.

From last November through March, the Department of Agriculture sharpshooters, armed with night-vision goggles and high-powered rifles, killed 377 deer, reducing the herd to 374, down from 1,277 before the shooting began, the park service said.

However, the population numbers will increase with fawning — an estimated 175 fawns were born last year — and the 2012-13 shootings will occur as planned, said Kristina Heister, the park's natural-resource manager.

Meanwhile, the park said about 11,500 pounds of deer meat had been donated to the Central Pennsylvania Food Bank, bringing the two-season total to nearly 30,000 pounds.

The park service said that before the culling, the deer herd had jumped eightfold in 25 years, and that overpopulation was having a deleterious effect on plant life. Deer are vegetarians, and consume five to nine pounds of food a day. A Pennsylvania analysis of deer stomach contents found 98 different plants. Deer also were crowding out some animal life, including ground-nesting birds, it said.

In 2009, the park's deer density was estimated to be 241 per square mile, the park service said, and the recent cullings have brought it to 71. The target density is 31 to 35 per square mile, or a total of 165 to 185 deer.

Deer issues are hardly unique to the park. Valley Forge's represent a variant of tensions common in other developed areas and adjoining park lands elsewhere in the country, as a once-endangered species has enjoyed a dramatic comeback.

In the early 20th century, hunting and predation had so reduced the whitetail deer population that the Pennsylvania Game Commission began importing the animals.

However, spreading human development has been a bonanza for the whitetail, routing predators, limiting hunting activity, and supplying a smorgasbord of backyard plantings.

Culls, in which deer are lured to baited areas and then shot, and controlled hunts have become more popular. A culling program began in 1995 at Gettysburg National Military Park, and by last winter the herd had been reduced by 90 percent, with an average of 150 killed annually.

The Valley Forge program is scheduled to consist of two more seasons of shootings, and after that might resort to birth-control methods. Over the 15-year life of the program, the total cost could go as high as $2.9 million.

Contact Anthony R. Wood at 610-761-8423 or twood@phillynews.com