If you’re looking for an adventure this weekend, why not take part in a scientific exploration… of your backyard?

The seventh annual Great Backyard Bird Count takes place Feb. 13-16, and it’s one of the few times you can contribute to science, learn more about the world around you and experience nature, all in less than half an hour.

The Cornell Laboratory of Ornithology in Ithaca, N.Y., and the National Audubon Society use the results of the count to gauge how different species are doing and how weather, illness and other factors are affecting bird populations. You might think there isn’t much to learn from a bunch of people taking a few minutes to count birds out back, but because so many people participate in the count, the combined results provide important statistical evidence.

Last year, more than 50,000 checklists were submitted to the bird count Web site, www.birdsource.org/gbbc. Participants counted 512 species of birds, and more than 4 million individual birds.

"This gives us something more to go on in terms of evidence," said John Bianchi with the National Audubon Society.

One finding of last year’s study was a sharp decline in the numbers of American crows seen in Midwestern states, possibly caused by the West Nile virus. A few years ago, researchers were surprised by the large numbers of robins seen nationwide in the count. Robins usually hide in bushes during the winter eating berries, but unseasonal temperatures kept them out in plain sight, eating their warm-weather diet of worms.

"We didn’t realize that weather effects robins in that way," Bianchi said. "The count is showing us some interesting, unexpected things that we’re able to verify in real time."

With so many people participating, the bird count is also a good way for the Audubon Society to let more people know about protecting bird habitat in their yards and to get beginning birdwatchers interested in helping with other bird counts and conservation projects.

"This count is very focused on beginners," Bianchi said, "trying to get the people with the bird feeders and the binoculars and the bird book involved. There are 71 million birders out there. We hope to get them to help us."

Allison Wells with the Cornell Lab of Ornithology said the count is set up to make it as easy as possible for beginners.

"Some people think that they’re not qualified to participate," she said. "Everything they need to know is at the site. Everything they need to learn about birds."

Sally and Jan van Niel plan to do their head count around their Mountlake Terrace home. Sally van Niel is the president of the Pilchuck Audubon Society, and she and her husband were two of the founding members of the society.

The van Niels have seven birdfeeders outside their home. Two are stocked with thistle seed, three with black sunflower seed, one is a suet feeder and one is filled with sugar water for hummingbirds.

"We have all kinds of feeders because we like all kinds of friends," Sally van Niel said. "Different things attract different birds."

At various times of the day, pine siskins, house sparrows, chestnut-backed and black-capped chickadees, bushtits, downy woodpeckers, Anna’s hummingbirds, house finches, dark-eyed juncos and spotted towhees visit the feeders. That can make the van Niels’ yard a pretty lively place.

"Some morning they’re just all over the place," Sally van Niel said. "Every once in a while, you won’t see any birds at all. That’s because there’s a small hawk that perches on a tree around here and feeds on the birds (sending them into hiding). We don’t catch the hawk directly at it, but we do see the effect."

Although the van Niels are passionate birders — Jan van Niel fills the feeders nearly every day, even bringing the hummingbird feeder inside to thaw when it freezes over, so the hummingbird won’t go hungry — they do not generally sit around the house counting bushtits and sparrows.

"It’s not something where we spend hours sitting here specifically watching birds," Jan van Niel said.

"We have these feeders right outside the dining room window so we can sit here and eat and watch the birds," Sally van Niel said. "It makes it easy."

For the Great Backyard Bird Count, all you need to do is spend a minimum of 15 minutes counting the greatest number of a species you see in one spot. That is to say, count four sparrows if you can see all four at once, so that you don’t count the same bird several times.

If you’re motivated, you can also submit more than one count, or visit a park or another area. The bird count Web site has a checklist with common birds for each region to prevent novice birders from skewing the count with misidentifications, and it has a bevy of tips for attracting and identifying birds.

The van Niels recommend newcomers pick up National Geographic’s "Birds of North America," or David Sibley’s "The Sibley Guide to Birds" as an identification aid.

Then just take a look outside and see who’s visiting.

"You put out a few feeders," Jan van Niel said, "and birds will come."

Reporter Andrew Wineke: 425-339-3465 or wineke@heraldnet.com.