When Peter and Claire Berlin talk about nature, they don't sound like teenagers.

Peter, 17, a rising senior at Osbourn Park High School, can tell you the benefits of prescribed burning (setting fire to plants to regenerate growth). And Claire, 14, a home-schooled sophomore, can explain how ovenbirds got their name (they build oven-shaped nests) and where they like to live (in deep forests).

The two spent much of their summer -- about 300 hours, Peter estimates -- learning these and many other facts.

"[My friends] think I'm crazy," Peter said.

Their work paid off last week.

Peter and Claire, who live near Manassas, and their teammates -- Aaron Bailey, 15, of Manassas, and Joseph Gordon, 17, of Appomattox County -- edged out 21 teams from across the country at the National 4-H Wildlife Habitat Evaluation Contest in Blacksburg, Va. Peter, Claire and Aaron won the state competition in May and invited Joseph, one of the top scorers, to join their team.

More than 80 budding, high-school-age conservationists -- from as far away as Washington state and New Mexico -- squared off on who knew the most about nature.

On Friday, the three- and four-person teams were taken to a "secret" location in Jefferson National Forest and asked to devise plans for how to "manage" the plants and animals surrounding them.

Habitat management involves making a piece of land better for wildlife, said Jeff Kirwan, extension specialist with Virginia Tech's College of Natural Resources and one of the contest organizers.

The competitors "have to be able to read the landscape from the perspective of an animal and know what that animal needs," he said.

The team with the highest scores in the five categories -- including rural and urban management planning, on-site habitat management recommendations, identifying wildlife foods, and interpreting wildlife habitat from aerial photos -- won. Tennessee placed second and North Carolina third.

Many teams -- including those from Florida, Colorado and Texas -- had never been in an Eastern deciduous forest.

So how big of an advantage did local teams have?

Not a crucial one, Kirwan said.

When the contest was held in Idaho in 1997, for example, the Virginia team won for its "Rocky Mountain elk plan," he said.

"They had never seen a Rocky Mountain elk in their lives," he said. "If you're uneasy with your knowledge, you'll pay a lot more attention."

The Berlins heard about the program that holds the contest last summer through their 4-H club, which meets at Buckhall United Methodist Church near Manassas. Their mother, Nancy, is a project leader for the club and has taught botany and stream monitoring. She also home-schools Claire and her son Sam, 8.

Before she got involved in the program, Claire could identify little more than a squirrel. She knew "hardly anything" about wildlife, she said, and she wasn't necessarily eager to change that. "At first, it was just like, oh, it's another 4-H project," she said. "But part of it was wanting to learn something different. Obviously, it was hard to get myself to study sometimes. I was like, 'Why did I join?' But now, looking back on it, it was an amazing experience."

On Friday, more than 80 competitors were taken to Glen Alton, a mountainous 310-acre farm that dates to the Depression. Teams had an hour to create a plan for reviving the farm's orchard and garden, boosting its butterfly and frog populations and controlling the house sparrows, which were encroaching on the bluebirds' territory.

To attract butterflies, Peter said his team would plant butterfly weed, asters, dill, fennel and zinnias, which provide nectar and shelter for the insects.

"[Butterflies] also like to drink from pools of water," he said. "So we would build a water collection area using pea gravel."

They would introduce aquatic plants to draw frogs and destroy some wood sparrow nests to control that population.

The Berlins' team -- which was coached by their mother -- placed second in this category, called the urban management plan. They scored first in the rural plan. Peter Berlin placed first in the aerial photograph portion, and Aaron Bailey won in food identification.

The competition was run by the 4-H's Wildlife Habitat Evaluation Program, a natural resource program that teaches wildlife and fisheries habitat management to youths.

The 4-H is a national youth development program administered by land grant universities, such as Virginia Tech, and Cooperative Extension offices. The Cooperative Extension Service is a program of the U.S. Department of Agriculture.

Now, Claire is thinking about making use of all this knowledge about nature. She's considering careers in landscape architecture or horticulture.

"I'm not sure yet," she said. "I'd like to do something at least slightly involved."

Aaron Bailey, left, Joseph Gordon, Peter Berlin, coach Nancy Berlin and Claire Berlin. The Virginia team won the National 4-H Wildlife Habitat Evaluation Contest. Forest ranger Jesse Overcash discusses plant life. About 80 youths devised plans for "managing" plants and animals in Jefferson National Forest.