For a few hours Thursday, a group of home-school students examined birds with the dispassionate eye of scientists, identifying different species, checking their weight, measuring their wingspans.

The young researchers, ages 10 to 15, captured and banded about 20 birds, mostly varieties of sparrows, at Prairie Ridge Ecostation for Wildlife & Learning, a 38-acre nature center that serves as a research station for the N.C. Museum of Natural Sciences.

Bird banding is a universal technique for studying the movement, survival and behavior of birds. All the data the students collected will go to the National Banding Laboratory in Maryland, a central repository of information that researchers use to study birds.

"I would hope children would come away with a better understanding of how science is done," said Charles Yelton, curator of programs and technology at Prairie Ridge. "Our focus at Prairie Ridge is to teach people science by allowing them to participate in science. Science is a process and not just a collection of facts in a book."

The eight-week Citizen Science Investigation, or CSI program, funded by the pharmaceutical company GlaxoSmithKline, is designed to show students how researchers go about their jobs and to interest them in potential careers in science.

"It's really amazing how much you can figure out by putting a little silver band on a bird," said Shannon Gerney, 12, of Raleigh, as she held the tiny Carolina chickadee in her palm. "You can feel him trembling."

Gerney and the other students worked alongside museum ornithologists to record data in the logbooks about the birds: weight, wing size, sex, body fat and the presence of new feathers. They measured the birds' legs and then clamped tiny numbered bands on them.

To snare the birds, the researchers strung a half dozen mesh traps that resembled badminton nets in the fields. Every few minutes, a group of students and scientists would make the rounds to check the nets. They disentangled the birds and placed them in drawstring bags until they were ready to examine them.

Ruth Parsons, 10, of Raleigh said the experience changed how she viewed birds. She used to think birds were "little fluttery things" but gained an appreciation for their intelligence in surviving and finding food.

Daniel Himebauch, 11, of Raleigh said he had learned that different species of birds have different personalities.

"Some are more daring than others," Himebauch said. "They all have their own personality."

Some of the captured birds already had leg bands, indicating they had been tagged before. The scientists recorded data to see how the birds size and weight had changed.

When a well-nourished Savannah Sparrow tipped the scales at 19 grams, John Gerwin, the state ornithologist pronounced, "What a buff bird!"

Gerwin said migratory birds are putting on a lot of fat right now to help them have energy reserves to make long flights northward for the summer. He blew on the birds' feathers through a straw to examine the skin color and see how much fat they had.

"They're filling up the gas tank," Gerwin said.