Things That Work: The Globe and Mail looks at businesses, services and other projects in British Columbia that aren't often talked about because they actually work.

It was snowing and the streets mostly hadn't been plowed but David Boyd knew the six volunteers he was counting on were going to show up for the 117th annual Christmas bird count.

In fair weather and foul for about 30 years, Mr. Boyd has been co-ordinating the count in the South Vancouver and Marpole areas as part of a massive, continent-spanning effort that is North America's longest-running citizen science project.

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Of all the things that work in the city, few can claim to work as consistently or for as long as the Christmas bird count.

"We've had to delay a few, but have never cancelled," Mr. Boyd said of his count, which this year recorded 44 different species, mostly around Langara Golf Course and in some pocket parks and green strips of land near the south arm of the Fraser River.

Across North America, thousands of participants identify and record birds on one day that falls between Dec. 14 and Jan. 5. They work in a prescribed circle about 24 kilometres in diameter.

Mr. Boyd, who first began Christmas bird counts in the early 1980s, said he does the count because he enjoys it, even when the weather is bad, as it was when he did his last count on Dec. 16.

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"I get a great thrill out of watching birds and I get a lot of pleasure also in seeing other people enjoy it," he said.

"It attracts quite a few people who are very tentative about birding. They feel they aren't adequate, but, if you put them with someone who has birdwatching skills, it often quite inspires them."

Dr. David Bradley, B.C. program manager for Bird Studies Canada, said the thousands of volunteers who turn out each year in the province to help with the count have fun, but they also contribute important scientific data.

"Like with any citizen science project, there's going to be some observational error and … it's going to be higher than if you have trained scientists going out. That's understood," he said.

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"But you standardize it as much as possible. The location, the time they go out and … usually each team has an experienced leader who can help train others and help correct for identification mistakes. There is always going to be error, but the idea is if you collect enough data the errors will be smoothed out."

Dr. Bradley said the Christmas bird count is a valuable tool in tracking broad trends in bird populations. "This is a really good long-term data set."

Around B.C. last year, there were 99 separate counts involving 2,864 volunteer field observers and another 633 people who did counts at their backyard bird feeders.

About 165 volunteers – including the half-dozen with Mr. Boyd's circle – were in the field in Vancouver, and five did feeder counts.

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In total, 217 species were recorded provincewide in the 2015-16 count. The latest numbers are still coming in.

Last year, waterfowl numbers were up in B.C., with big increases in the cackling goose and Canada goose (2,168 and 55,383, respectively) and a record number of bufflehead (19,089), mostly in the Southern Gulf Islands and on southern Vancouver Island.

According to Bird Studies Canada, the number of Pacific loons also increased with almost 7,000 counted, including a remarkable flock of 2,712 off Rose Spit in Haida Gwaii.

While birdwatchers like to record big numbers, they can get even more excited by rarity.

"The most unusual bird for the count was likely the Canadian Christmas Bird Count's first Siberian accentor," Bird Studies Canada reported of a sighting in White Rock that triggered a "rare bird alert."

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The small songbird had somehow strayed – it breeds in Siberia and winters in Southeast Asia – and might not have been seen except for the Christmas bird count volunteers.

Mr. Boyd hasn't seen any extremely rare birds during the Christmas bird counts he's done in Vancouver, but there are often uncommon species that generate some excitement.

"One year, we had a rough-legged hawk which in an urban area is quite unusual, although you can see them in Richmond and Ladner," he said.

Over the years, he's noted some significant changes in Vancouver's bird population, with some numbers going up and others falling dramatically.

"A plus is Anna's hummingbird. At the golf course, the first [ever sighted there] was in 2008 and now we regularly see eight," he said.

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"On the other hand, when you look at swallows, it is a bit of a disaster. You used to see swallows lining the power line down the lane and you don't see that any more."

That and other pieces of data collected by volunteers during the Christmas bird count are helping scientists understand how habitat and climate changes are affecting birds.