The raccoons can be annoyingly pesky. And skunks tend to raise a stink when denied the right of way. But the biggest problems, conservation officer Gilman Aldridge said, are caused by beavers.

"When they go and chop down somebody's prized dogwood tree, the citizen wants to get that beaver. They also want to get the park authority," sighed Aldridge who is responsible for the increasingly wild kingdom of Fairfax County.

Amid the tract housing developments and interstate highways the suburban county is noted for, Aldridge said, deer, possum, skunk and even black bears are making a comeback. And the mammal boom has not been limited to Fairfax. From Bethesda to Beltsville, homeowners are reporting, often in shrill tones, the ravages of raccoons and possums on trashcans and backyard flower beds.

The return of country critters to citified living has provoked confrontations, not only between man and beast, but also between hunters and animal rights groups.

"Trying to control squirrels, raccoons, deer and people at the same time is a tough job and one I'm not prepared for." said Aldridge Wednesday night in the middle of a protest over a park authority program.

A planned demonstration of hideskinning and tanning at the Hidden Oaks Nature Center in Annandale had attracted a dozen hunters, interested in learning how to make use of animal pelts, and a group of animal lovers opposed to the whole idea.

Carrying placards that read "Skinning Is a Sick Hobby" and "Mutilation Is Not Education," the protesters from half a dozen area humane societies transformed the seminar into a media event.

"Animals should not be treated like inanimate objects," said Andrea Posner, a member of People for the Ethical Treatment of Animals. She maintained that most hunting is done for "trivial" reasons of "sport and vanity."

In a concession to the protesters, Aldridge changed the program which was supposed to include the skinning of a raccoon which had been killed by traffic.

Instead, Jim Banton, a park authority naturalist, used sketches of a raccoon and squirrel during his 25-minute lecture.

"You can't please everyone," said Aldridge who announced that because of the controversy, the authority's fourth annual hide-tanning seminar would not be held next year.

For Aldridge and 15 staff members, the protest was only a dull ache compared to the long-term headache caused by overpopulation of wildlife in the Washington suburbs.

"The beaver problem in Fairfax County is getting horrendous and nobody knows what to do," Aldridge said. The largest concentration of beaver are along Accotink and Pohick creeks in the western part of the county. "Between the upper end of Lake Accotink and the city of Fairfax there are a potential 100 beavers," said Aldridge.

An increase in the deer population in the wooded land beside the Dulles Access Road has led to a number of deer-cat collisions the last year, said Aldridge, who is more concerned for safety of drivers than the deer in those encounters.

Then there are sightings of black bear during the past month near the Capital Beltway in Fairfax.

"They are not dangerous as long as you leave them alone." Fairfax County game warden Ralph Stickman said. But park officials worry that a chance meeting between a hiker and a bear could be dangerous.

The return of wildlife to Northern Virginia is credited by conservation officials to a lack of natural predators, a mammalian talent for adaptation to new environments and the recent antipollution efforts which have, among other things, made the Potomac River a more attractive home for beavers.

Kathy Lyon, acting director of the Animal Welfare League of Arlington, is not sure the surge in sightings is necessarily the result of an increase in population. "The speculation is that all the new construction is displacing those animals so that people are just noticing them more. They have no place else to go but to peoples' homes," said Lyon, whose office rents raccoon traps to Arlington residents.

Wildlife officials, faced with the need to control mammal populations, complain they have neither the budgets nor the technique for accomplishing that. Leg traps and poisons are considered too cruel. Hunting in urban areas is dangerous. And live trapping is too expensive.

"We need a new program for urban wildlife management," Aldridge said after the skinning lecture.

As he spoke, the conflicting groups of hunters and humane society representatives gathered in separate bunches, neither completely satisfied with the night's program.

"I wasn't dented at all," said John Grimm, one of 13,398 licensed hunters in Fairfax County. "It didn't seem like what they (the protesters) had to say hit the mark."

Lorraine Hajeski guided her 7- and 9-year-old sons between the groups for a short walk home.

"My kids haven't learned a thing from this.It's been brought up to a debate level rather than an educational one." Hajeski said, "I don't really care one way or the other; I just thought they might learn where leather belts come from."