Any night now, the blood will flow again in Valley Forge National Historical Park, and hundreds will ultimately die. Deer, that is.

The park is set to begin its second annual deer-culling operation, in which U.S. Department of Agriculture marksmen with rifles and night-vision goggles take aim at deer lured to baited sites.

Citing safety concerns, the park won't disclose the dates of the shootings, only that they would occur between November and March. Last season, sharpshooters took out 600 deer, and the park aims for 500 this time, said Kristina Heister, the park's natural-resource manager.

Animal-rights activists, who filed unsuccessful legal challenges to the cull, are appalled. They want the park to "rethink its management policies," said Lee Hall of Friends of Animals. "The ecological goal should be enabling animals on public lands," she said.

But Valley Forge is simply one more battleground in the escalating conflict between homo sapiens and the once-endangered odocoileus virginianus. Variants can be found all over the country where development abuts woodlands.

A similar cull will take place in Lower Merion Township in December, and controlled hunts are scheduled in coming weeks at Ridley Creek State Park in Delaware County, Tyler State Park in Bucks County, and Wilson Farm Park in Norristown. Many state parks and forests in New Jersey, where more than 55,000 deer were killed last year, permit hunting.

How did a species traditionally associated with pastoral tranquillity become such a pariah, viewed as a health and safety hazard, especially at this time of year?

For one thing, even though the deer population has declined statewide, said Duane Diefenbach, a Pennsylvania State University wildlife expert, it has exploded in urbanized areas. Development has been the biggest boon to the deer population since the vanishing of the North American ice sheets more than 10,000 years ago.

Housing and commercial development on woodland borders have chased out predators, limited hunting, and served up a delightful variety of backyard plants for discerning deer.

"It's likely the state has more deer now than before Europeans showed up," Diefenbach said.

The result has been more contact between deer and humans, with sometimes unpleasant results.

In a well-publicized incident this month, for example, a buck wandered through the open front door of a Sprint store in the Gateway Shopping Center in Tredyffrin Township, not far from Valley Forge.

Perhaps thinking he saw a rival buck, he charged into the bathroom, smashing a sink, not realizing he was looking at himself in a mirror. "They don't know what mirrors are," Diefenbach said.

He added that the buck may well have been in a hormonal frenzy. This is mating season, when deer are prone to erratic behavior, and state officials in New Jersey and Pennsylvania warn motorists that this is peak collision season.

Insurance experts estimate there are 130,000 deer-vehicle collisions annually in Pennsylvania and New Jersey.

Deer also are known to be efficient distributors of Lyme-disease-bearing ticks.

But neither crashes nor Lyme disease are issues at Valley Forge.

The park estimated that before the cull began last year, the deer population had increased eight-fold over 25 years - to 1,227, or 241 animals per square mile. Deer were consuming forests and crowding out some other life forms, Heister said.

The Valley Forge goal is to reduce the herd to 165 to 185 deer per square mile under a 15-year program estimated to cost $1.8 million to $2.9 million. After four years of controlled kills, the park would resort to a birth-control agent, should an effective one become available.

Heister said that it would take years to assess the results of the deer-control program but that she had already seen evidence of renewed growth in some spring wildflowers.

In the meantime, the cull also has been a boon for food banks.

The park said last season's kill resulted in the donation of 18,330 pounds of venison.