WEST GLACIER - When Pleistocene ice finally retreated some 12,000 years ago and fish first recolonized the waters in what is now Glacier National Park, one of the first residents to reclaim a home here was the common loon.

Of course, there's nothing common about these ancient birds - not their habits nor their haunts nor their Loch Ness look, and certainly not their mysterious call, the song of wildness itself. There is not, in fact, even much in the way of common knowledge when it comes to the common loon.

"What we don't know," said Steve Gniadek, "would fill a book or two."

The first books, written from Glacier in the early 1900s, reported loons all over the park, said Gniadek, a wildlife biologist with 20 years experience tromping the park's wilds.

And then, for a chapter spanning a half century or so, no one really looked for loons, not until the 1960s, when renewed monitoring tracked the birds on a half dozen park lakes.

Increased patrols put loons on 10 lakes by the 1970s, well over a dozen lakes by the 1980s.

It was a matter of more lookers, Gniadek said, not more loons.

In fact, some lakes have lost loons, and no one knows why.

"I'd certainly like an answer to that," Gniadek said.

But the problem with wildlife research in this wilderness park, he said, is the problem of sheer numbers - 1 million acres divided by just a handful of scientists. It was obvious from the start that his staff would need help from hikers.

Enter "Loon Day," an annual mid-July event since the late 1980s, a day for counting loons on waters all across the region. The celebration of loons is a yearly snapshot, a single-day survey in which a small army of professionals and amateurs take to the field on the hunt for a glimpse of Gavia immer.

Since 1989 - which Gniadek uses as Year 1 in his "Loon Day" calendar - hundreds of volunteers have helped keep track of his loons. More and more lakes have been visited, year after year, and 45 particular park waterways have proved consistently loony places.

Still, no matter how many more lakes they hiked to, the volunteers always counted pretty much the same number of birds in Glacier - right around 40 each season, suggesting a relatively stable population.

But was the population really flat, or was the one-day snapshot insufficient to plot real trends? And what was happening in those places where loons seemed to be disappearing?

And could Gniadek really rely on his amateur volunteers? After all, some were reporting loons in pretty improbable places, places far more likely frequented by the common merganser, which can look uncommonly like the common loon.

One fellow, Gniadek said, insisted he'd seen loons with herds of youngsters in tow, despite the fact that loons have only one or two chicks each year. But when the biologist suggested the volunteer in fact might have spotted a mama merganser, "he said he knew what a loon looked like because he was from Minnesota," Gniadek said. "I don't know, it must be genetic there or something."

Clearly, Gniadek needed not only a way to plot trends, but also to train his flock of helpers.

So he printed up posters and pictures and placards with detailed descriptions, even included maps so observers could better pinpoint their sightings, and for a few more years he hobbled along with what help he could find.

And despite the limitations to this nascent "citizen science," he said, the verified loon reports began, finally, to show hints of trends.

Some were encouraging - 35 lakes with loons by the mid-1990s, and 13 lakes with chicks.

Some were troubling - lakes in the park's northeast had apparently lost their loons.

The monitoring also highlighted for Gniadek the importance of tracking loons in Glacier. His park, it turned out, was home to a full 20 percent of Montana's breeding pairs, and a mere four lakes were producing more than half of Glacier's baby loons.

Finally, he could focus, and could begin to ask more pointed questions.

Science already knew loons are old - just look at those hesperornis fossils, evidence that proto-loon lived alongside dinosaurs in the late Jurassic. They're genetically complex, closely related to penguins and albatrosses, and can excrete salt just like those seabirds.

They're socially complex, too, living their first four years entirely on the open ocean before beginning the ocean-to-mountain migration that might continue a full quarter-century.

What science didn't know were things such as how youngsters disperse when they leave the nest, where they go in winter, how long the migration takes and by what route loons travel. Gniadek wanted to know more about Glacier's loon population, its health and reproductive success and its chick mortality, so he could begin to understand how to best protect this "species of special concern."

And for that, he would need both a bigger army and a longer season - amateurs volunteering all summer long and not just for a one-day snapshot.

"Would I prefer a team of wildlife biologists?" he asked. "You bet."

But when it comes to basic park science, you take what you can get.

What Gniadek got, in 2005, was a $57,000 grant to kick off the official "Citizen Science Loon Project." He recruited more amateurs, trained more volunteers, crafted a formal curriculum about how to do field science and how to identify loons.

His research team improved its accuracy, increased its coverage, extended its season, expanded its observations.

Biologists even taught the citizen scientists how to look for particular behaviors, such as the frantic "penguin dance" or the loon's haunting tremolo call, both of which indicate a bird in distress.

All these observations, he said, will help park brass decide how best to manage their wildlands and their wildlife.

If volunteers observe sensitive loon nursery areas, for instance, managers might choose to open a nearby trail or road just a little bit later in the spring. Determining hatch and migration dates, likewise, could inform similar park decisions.

"The more we know," he said, "the better we can fine-tune our protections."

Citizen science certainly has proved its worth, and not just in terms of free data collection, said Jami Belt, project coordinator.

It educates people, Belt said, and so makes them advocates for stewardship. And it helps the experts pinpoint where best to spend their own limited field time, verifying solid baseline observations rather than collecting baseline themselves.

And, most importantly, the data collected is proving to be unusually high-quality data, despite the amateur observers.

In the three years of her program, volunteers have logged a whopping 7,655 hours in the park.

Certainly, Belt said, there are challenges, limitations to what you can expect from nonscientist scientists. You can't order them to be in a particular place at a particular time, can't control their inexperience, can't force them to fill out each and every portion of the detailed observation forms.

Citizen scientists like to go to pretty mountain lakes, sometimes, rather than swampy beaver ponds where loons are more likely to live. And they don't always show up at 5 a.m., when dawn is breaking and loons are active.

But despite all that, Belt said, "citizen science works, and without these volunteers we wouldn't be able to even do summer loon surveys. The volunteers are totally essential to what we're doing."

And the quality control, she said, is getting better all the time. Last year, only two volunteers turned in photos of "loons" that turned out, in fact, to be mergansers.

And both, ironically, were biologists, formally trained to do biological surveys, if not to study loons.

"It all boils down to the reliability of the data," Gniadek said, "and I believe our citizens are collecting very good data. We have become partners, in the best sense."

Wanted: citizen scientists

Get up from that chair and out of that cubicle, because Glacier National Park needs volunteer "citizen scientists" to help conduct field work this summer.

An ongoing project will track loons across Glacier's million-acre wilderness, while another group takes to alpine heights to follow the lives of mountain goats, pikas and Clark's nutcrackers. A third project is mapping invasive plants throughout the park's backcountry.

To join either the loon or weed work, call Billie Thomas at 406-888-5827. To get in on the goat, pika and nutcracker project, call Jami Belt at 406-888-7986.

Training will be provided to all volunteers, and the strenuousness of any given assignment will be tailored to individual abilities. All are welcome.