Jill Anderson likes to escape from her high-pressure job to a serene weekend world in which she can stroll through the woods in solitude.

She goes well supplied. Thousand-dollar binoculars, a $1,200 spotting scope with tripod, a digital camera and a Palm Pilot for her bird checklist make communing with nature all the more enjoyable.

Thanks to modern nature lovers such as Anderson, 45, a growing amount of money is going to the birds -- actually, the pastime known as bird-watching.

"My father would die if he knew how much I spend on birding," said Anderson, a psychotherapist, who admits to shelling out thousands of dollars a year on her healthy obsession.

The River Forest, Ill., resident has plenty of company. Bird-watching is the nation's fastest-growing outdoor activity, according to a recent U.S. Forest Service survey. While only a third of the estimated 70 million Americans who bird-watch every year are serious birders, the Forest Service says the total of those participating has more than tripled in 20 years.

As with many trends, baby boomers are shaping this one.

The survey found that the typical birder is 52 -- at the upper end of the generation born from 1946-64 -- well-educated and affluent, with significant discretionary income. Bird lovers already are spending a fast-rising amount on their pastime, and as boomers retire, it's expected to soar much higher.

Today's birders shop for fancy gear on the Internet or choose from among hundreds of specialty stores that offer nifty ornithological stuff -- a thriving retail business that didn't even exist two decades ago.

For the back yard, there are redwood feeders with hand-cut shingle roofs for $400 or more, copper-roof feeders for $300, blown-glass hummingbird feeders, heated bird baths, recirculating pump ponds, multiple-feeder stations, drippers, misters, nesting boxes, squirrel baffles and, of course, birdseeds galore.

Then there are computer software databases, birdsong CDs, birding vests, special cameras, scopes and other gadgets, not to mention shelves full of bird books.

But what really makes birders go weak-kneed and reach for their credit cards is a fabulous pair of binoculars.

"Just about every bird-watcher is in pursuit of the perfect binoculars," said Vic Berardi, 49, a plastics-company sales manager from Gurnee, Ill., with a passion for hawk-watching. "You'll see birders spend $800 or $900 on a pair of binoculars, and then three or four years later they'll do it all over again."

Berardi knows that temptation well, having just bought "the best pair of binoculars I ever looked through in my life" -- and the most expensive, at $1,400.

It's a far cry from the days not long ago when birding was a no-tech activity for total geeks, according to bird enthusiast Alicia Craig.

When Craig, 43, of Indianapolis, was younger, "we didn't want to be caught dead with a field guide and binoculars in hand."

Now she has 17 feeders in her back yard but is hardly a geek. She makes a living from the birding trade as senior manager of nature education for Wild Birds Unlimited, a franchise system of more than 290 hobby stores throughout North America.

Birding not only proved a profitable business during the big-spending 1990s, she says, but also is showing staying power as boomers age and seek respite from fast-paced lives.

"Especially since September 11, people are really searching for things they can do with their families, things they can do close to home, things they can do more to give them peace of mind," Davis says. "Bird-feeding and bird-watching can be very tranquil."

It can be a very inexpensive sport or one that serious birders spare no expense to pursue. One can stay at U.S. bed-and-breakfast inns for bird-watchers, or travel to South America to see rare hummingbirds, or maybe to Madagascar for bee-eaters or Sri Lanka for lapwings.

"I'm struck by how much money some people are willing to spend just to see a bird they haven't seen before," says Will Weber, who organizes trips for birders as co-owner of Journeys International in Ann Arbor, Mich.

A lifelong birder, Weber, 55, well understands the thrill of birding and connecting with nature.

"I can fantasize I'm living 100 or 200 years ago, getting out in the woods and using all my environmental skills to identify birds," he says. "There's that sense of mastering something that doesn't require tremendous physical skills."

Anderson used her expensive equipment to snag a sensational close-up photograph of a great horned owl in a forest outside Chicago this month, holding a digital camera up to her scope. But even without pricey gear, she said, birding is time well-spent.

"Just being out there, I find it very peaceful," she said. "I get a balance from that. You value the open land and everything that's in it."

Brian Neiman of Wild Birds Unlimited of Lisle, Ill., sells bird seed to Jill Anderson, who spends thousands of dollars each year on bird-watching.