The Eurasian collared-dove was introduced into North America about three decades ago, escaped captivity in the Bahamas and eventually reached Florida sometime in the early 1980s.

The Eurasian collared-dove was introduced into North America about three decades ago, escaped captivity in the Bahamas and eventually reached Florida sometime in the early 1980s.

As wily birds tend to do, this smart, adaptive cousin of the pigeon spread its wings and took flight across the United States. In 1999, during the Great Backyard Bird Count, it was recorded only in a handful of Southern states; last year, backyard birders found it in 39.

Few of those who tracked the dove's colonization were professionals. Even fewer had ornithology degrees. The majority were volunteers who love birds and took some time to look out their windows and write down whatever birds they saw.

Scientists can't be everywhere at once. Everyday birders can.

"We knew [the doves] were spreading, but how do you really see what's going on?" said Rob Fergus, a senior scientist with the National Audubon Society. "The Backyard Bird Count gives you a nice quick look. Then we can go back and see how significant the trends seem to be."

You can join in this citizen-science project Friday through Monday, Feb. 13-16.

All you need to do is count birds for 15 minutes on one or more days, record the greatest number of each type seen at once and submit your numbers to the GBBC site by March 1. You can participate in different locations and multiple days, submitting a list for each session.

This weekend, thousands of participants will brave the cold at local parks or sit by their widows, coffee in hand. They will observe from boats in the Keys, fire escapes in Manhattan and tiny apartments in German Village. Some will have decades of experience; others will simply join their crazy birder friends.

"It's just a great way to start to identify birds," Audubon spokesperson Delta Willis said. "As people cut back on travel and spending, this is something you can do in your backyard."

Last year, birders counted more than 9.7 million birds of 634 species and submitted nearly 85,000 checklists, crucial info for the Cornell Lab of Ornithology and Audubon, the event partners.

The data helps scientists map annual changes in distribution and abundance of birds and the effects of disease, climate change and urbanization.

"It's not the kind of thing where you're saying that five robins one year and six the next means a 20-percent increase," said Bill Heck, who leads the Avid Birders club of Audubon's Columbus chapter. "[It works] when you see thousands of people notice the same increase or decrease."

It's strength in numbers. You can be one of them.

Central Ohio backyards host a number of unique birds that are easy to identify, including the American robin, northern cardinal and Carolina chickadee. If you can't tell a white-crowned sparrow from its white-throated cousin, you can find a regional checklist and ID page on the Bird Count website.

But even regular birders sometimes see a special species when they're hunkered down in the name of science. This year's extreme winter weather could bring in some oddballs blown off course or hitting feeders because of icy conditions.

Similar events like Audubon's Christmas Bird Count have continued for more than 100 years, so they've compiled a rich pool of data to indicate whether a bird like, say, the evening grosbeak has thrived in the Midwest. The backyard count, now in its 12th year, is on its way.

"As with all studies, the more input you have, the more you can say what's happening," Fergus added. "We're just now, over the past five years, getting to the point where we can start doing analysis."