Headlamps pick out next steps and ears are perked as a crowd of 40 follows dark wooded paths near the Long Point Bird Observatory field station on Lake Erie. The chilly, nearly moonless late-October night is punctuated by the high-pitched toots of Northern saw-whet owls, which also make a long and shrill “skiew” sound when alarmed that resembles the whetting of a saw — truly eerie in the right setting.

But the calls are resonating from a stereo, and soon saw-whets come dropping from the treetops to investigate, only to be caught in the triangle of nets that surrounds the audio lure. They’re regular migrants through the area, and if it’s a good night Bird Studies Canada staff and volunteers will net, band, weigh and release up to 100 of the pop can-sized birds in front of the agog audience of schoolchildren and parents. For every 10 owls banded, one may be recaptured by another group elsewhere, sometimes halfway across North America; banding them mid-migration fills in key data gaps for what is still a fairly mysterious species. It’s cold and painstaking work, but it’s also exhilarating and totally gratifying. There’s a long list of people waiting for a turn to help.

“People say ‘That’s crazy,’ until they watch us on one of these banding outings or they go out in pairs on an all-night owl survey in April,” says Jody Allair, the Bird Studies Canada biologist and science educator who oversees the bird bandings, the country’s nocturnal owl surveys and a host of other programs. “And then they realize how magical it is. Listening to owls, having that night-time experience — people love it. These are important programs for us, and they provide the only population data in Canada for owls, period. No other surveys catch them. Owls are otherwise in a total loophole.”

So it is, to one degree or another, for any of non-profit Bird Studies Canada’s 20 main citizen science programs, which every year boast the eager participation of more than 30,000 Canadian birders — mostly regular civilians, not ornithologists or biologists like Allair. They’re the ones gathering the bulk of the data that’s essential to the “real” scientists, and to organizations that make official decisions about which species should be declared threatened or endangered, which land should be designated as conservation areas.

“There is no other ‘secret’ source of data out there that’s helping the federal government or Environment Canada make these decisions,” says Allair. “It’s almost exclusively citizen science data that they use, and that’s saying something.”

Crowdsourcing for scientific data has its critics — academics leery of potentially sloppy collection methods and otherwise flawed reports. In a number of fields, however, including ecology, astronomy and even medicine, crowd science has been affording researchers reams of cheap, far-reaching and surprisingly sound data for analysis, and making real contributions to real findings.

A recent example of this is a 2013 study in which populations of woodpeckers and the white-breasted nuthatch were found to have exploded in the Detroit area, due to the invasion of the infamous, and apparently appetizing, emerald ash borer. Data for the paper came from Project FeederWatch, a beginner-level program that asks people to keep track of the birds at their backyard feeders from November to April. It was founded in Ontario, at Long Point, in the mid-1980s and later taken North America-wide by Bird Studies Canada and the Cornell Lab of Ornithology.

David Bonter, a Cornell ornithologist, FeederWatch project leader and an author of the woodpecker study, explained to Science Daily in August 2013 that “Participants in citizen science projects contribute real, valuable data that allow us to tackle some major ecological questions related to invasive species, urbanization and habitat change, our changing climate or other factors.”

And these contributions are coming at a crucial time, because as headlines read during the 2013 BirdLife International World Congress in Ottawa in June, one in eight bird species worldwide is at threat of extinction. That helped underscore the importance of BirdLife International, which, with representatives from 121 countries, is the world’s largest nature conservation partnership. More than anything, though, the oft-repeated “one-in-eight” stat is a blunt reminder that habitats and food sources the world over are being disrupted or destroyed by big agriculture, forest industries and climate change.

Canada’s birds are faring better, but its aerial insectivore species (such as whip-poor-wills and chimney swifts), grassland birds (such as sage grouse and loggerhead shrikes) and shore birds (such as piping plovers) have suffered drastic declines. Aerial insectivores across central and southern Ontario, southern Quebec and the Maritimes, for example, have dwindled by more than 70 per cent. It’s an unsettling thought, but birds happen to be excellent indicators of the general health of the environment.

With species fluctuations this dramatic, it’s especially critical that data from Bird Studies Canada’s citizen science programs is as accurate as it can be. To polish out the occasional faulty report from well-meaning but mistaken birders, they use a combination of automated data-filtering technology, staff and armies of volunteer experts, who review records and flag rare sightings and otherwise dubious entries. A number of the programs also provide training materials or run education sessions for participants.

“Hey, an osprey!” says Allair suddenly, in the middle of explaining the ins and outs of a Maritime shorebird conservation program. He’s staring out the window of his office at the Bird Studies Canada headquarters in Port Rowan, Ont., just around the corner from Big Creek National Wildlife Area and Long Point Provincial Park. The large raptor immediately catches his trained eye as it glides by, and in that workplace binoculars are never out of reach. “I’ll be entering that into an eBird checklist as soon as we’re finished talking. That’s the way it’s done,” he laughs.

eBird is a massive database of millions of geotagged species sightings entered by tens of thousands of birdwatchers across the world. The Cornell and National Audubon Society-founded program gives researchers, conservationists and other non-profits a constant, free source of dynamic information about where and how abundant birds are and their daily, not just seasonal, movements.

eBird is a glowing example of widely successful citizen science — broad in scale and relatively simple to use, it’s a powerful tool with a huge community. Bird Studies Canada, nevertheless, which uses every scrap of data possible to “advance the understanding, appreciation and conservation of wild birds and their habitats,” still depends most on the birders in its entry-level programs and more advanced breeding bird “atlases.”

A biologist in British Columbia’s lush Okanagan Valley, Dick Cannings likes to say that the region has the highest diversity of breeding birds in North America — a claim no one has challenged yet. He would know, though. Cannings has authored numerous birding guides, including Birdfinding in British Columbia, and he’s the Canadian co-ordinator for eBird, the B.C. Breeding Bird Atlas, the Great Backyard Bird Count and the Christmas Bird Count.

The Christmas count was invented by American ornithologist Frank Chapman in 1900, and is now carried out in more than 2,000 locations between Canada and Latin America. Bands of birders go out for part of any day during the Christmas season to identify and tally as many birds as possible in a 24-kilometre-wide circle, to which they return each year. Data from the survey has contributed to a number of species being added to Canada’s Species at Risk Act lists. One, the rusty blackbird, was seen to have declined by between 85 and 95 per cent throughout North America during the last 40 years.

“And Christmas just isn’t Christmas without the bird count,” says Cannings, whose father founded the Penticton, B.C., Christmas Bird Count in 1958. Cannings was just six years old when he first tagged along on the outing. His own son Russell, 26, also shares the family passion; this year he was travelling, so he sent in his Great Backyard Bird Count numbers from Borneo, Indonesia.

That was possible because as of 2013, data entry for the backyard count, which is a bit less methodical than the Christmas Bird Count, has been integrated with eBird, which means the program has gone global. Perfect for beginners and families, it occurs each year over a four-day window, usually on the third weekend of February. (And in spite of its name, it’s not limited to backyards.) “It’s designed to get as many people as possible involved at one time, to take a snapshot of the birds of the world,” says Cannings. “Generally, the easier observations are to report, the more popular the program is. That’s true of the Great Backyard Bird Count, because all we ask is that people go out, for 15 minutes if they like, and tell us what they saw.”

Easy spotting and reporting can be a plus, it’s true. Many birders, though, are a special breed — one that doesn’t wince before setting out on a damp and bitter early morning, or when they’ve braved backcountry bush for hours without catching a glimpse of a prized species. It’s also common for them to be natural “listers,” to make checklists for the day, for the year, for every province they go birding in, or for life.Breeding bird atlases suit these compulsions to a tee.

Each atlasing effort lasts for five years and happens once every 20 years. A province or region (British Columbia, Manitoba, Ontario, Quebec and the Maritimes have atlases) is cut up into a patchwork of 10-square-kilometre chunks, and volunteers are assigned to each. They’re responsible for making regular visits and for finding and listing evidence of as many birds as they can in that square, though they’re free to scope out birds in other blocks.

Becky Stewart, Bird Studies Canada’s Ontario program manager, recently moved to the Lake Erie office from Sackville, N.B., near the Bay of Fundy. She used to see the Atlantic staff of six swell to 20 in the summer, with a few hundred volunteers. While she was co-ordinating the Maritimes Breeding Bird Atlas between 2006 and 2010, more than 1,000 citizen scientist birdwatchers were logging data for that project alone.

“These volunteers love their birds,” says Stewart, “and when they’re ‘atlasing’ they know they’re adding to an important conservation planning tool, and helping to preserve their favourite pastime and species. Because of that they’re beyond motivated.”

Breeding bird atlases are staggering data collection and mapping undertakings managed by Bird Studies Canada, Environment Canada and regional partners. They provide the most detailed summaries of what’s going on, not just of bird distribution, but of productivity and relative abundance throughout entire provinces. Atlasing demands a level of expertise and dedication that can be daunting to novice bird spotters, but that doesn’t mean the programs don’t have a mix of neophytes and seasoned veterans. “There are always people to help, there are always more training opportunities and there are always other ways to learn more,” says Allair. “It’s a big responsibility, but people love it. In years after they often say that they can’t wait to have another atlas.”

When the second Ontario atlas was published in 2009 (the first happened in the 1980s), it was soon clear that a lot of birds had disappeared and habitats had shifted. “Suddenly all these species were officially going on the Committee on the Status of Endangered Wildlife in Canada’s lists (COSEWIC), and provincially all these birds that were suddenly listed as threatened or endangered,” Allair says. “The whip-poor-will is one of those.” As a result, there’s now a whip-poor-will roadside survey, the waiting list for which is long and full of people determined to help save the moonlight-loving insectivore with the iconic call.

Similar patterns are being found in the second Maritimes Breeding Bird Atlas. Stewart points to the impact that different forestry practices and other human uses of the landscape have had on bird populations and distribution. “In the Maritimes the forest industry is fairly focused on promoting coniferous forests and shorter harvesting cycles,” she says. “You can see that birds that use that type of habitat have increased in numbers, and that there are far fewer of the species that depended on the forests that aren’t there anymore.”

It can be discouraging for birders when a species doesn’t return to its habitat, but it can be even more important to mark its absence.

Charlotte Wasylik watches birds in the wetlands near her Prairie home in Vermilion, Alta., using a sleek Swarovski ATM 80 scope that she bought with her savings. Her favourite species include the cinnamon teal, a small dabbling duck that breeds in the area in the spring, and the white-fronted goose, which migrates through eastern Alberta and nests in the Arctic.

She was 11 when she noticed the American goldfinches darting about her yard in the summer, and when her parents bought an identification book she discovered that she couldn’t get enough. “There were so many species that I didn’t know about; it just hooked me,” she says.

That wasn’t that long ago. Now 16, Wasylik has been to Bird Studies Canada’s Long Point headquarters for their Young Ornithologist Workshop and returned in the summer of 2013 for a month-long internship. There, with other young birders from British Columbia, Ontario and Quebec, she learned how to study birds in the field, properly handle and band, determine age and sex and prepare specimens for studies.

Whether Wasylik turns her interest into a career as an ornithologist or conservationist, or continues to foster it as a side obsession (her word), she’s already contributing to the welfare of bird species and the protection of vital habitat. When asked “why try these citizen science programs?” she doesn’t miss a beat: “Birds are just so important to the planet. If a lot of people knew more about them they might understand more about biodiversity too. When we lose birds, we lose so much more.”

For a complete list of Bird Studies Canada’s citizen science programs and to find out more about volunteering, visit bsc-eoc.org/volunteer.

More than 30,000 Canadian birdwatchers take part in Bird Studies Canada’s citizen science programs each year. (Photo: Christopher Di Corrado)

Jody Allair of Bird Studies Canada holds up a Northern saw-whet owl, netted during a bird-banding event in Long Point Provincial Park, Ont. (Photo: Jeff Tribe)

Banding programs and nocturnal owl surveys provide researchers with the only comprehensive population data for owls in Canada. (Photo: Jeff Tribe)

Canadian birdwatchers' observations play a major part in the conservation decisions of Environment Canada and other organizations. (Photo: Catherine Jardine)

Habitat loss at stopover sites and in wintering grounds may be the biggest threat to many bird species, as well as climate change, pollution and pesticides. (Photo: Eric Demers)