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Christmas Bird Counts occur across the Americas

Citizen science observations made during annual Christmas Bird Counts allow researchers to determine bird population trends and range changes. We have learned, for example, that if climate change worsens, Red-bellied Woodpeckers will lose part of their western range while their range to our north will expand. Photo by Paul Nicholson.

Bird watchers were the first to harness the power of citizen science. In 1900, the original Christmas Bird Counts – or CBCs – took place in Toronto and in 24 other North American cities, making it the world’s longest-running citizen science initiative. A decade later, the annual count had started here in London.

CBCs are now conducted in more than 2,000 communities across the Western Hemisphere including in more than 100 Ontario cities and towns. Bird watchers are assigned to routes within count circles, each of which is 24 km in diameter. The circles and most of the routes within them remain the same every year.

Each year in Canada alone, millions of individual bird sightings by more than 10,000 birders in the field and more than 3,000 citizen scientists counting feeder birds are recorded. The crowd-sourced data are uploaded then automatically consolidated for use by research scientists.

Over the decades, birders’ data have revealed interesting population trends and range changes for species such as the Carolina Wren. London has the all-time Canadian high CBC count for Northern Cardinals, earning it the “Cardinal Capital of Canada” nickname.

More recently, bird data are being studied to get an enhanced understanding of the impacts of climate change. Bird scientists with Audubon looked at more than 100 million bird observations to develop climate models that predict how species’ ranges will change. For example, if climate change worsens, the Red-bellied Woodpecker will lose part of its western range while its range to our north will expand. The impact of various warming scenarios and other details can be viewed on the Audubon webpages.

The classic CBC counts always occur between December 14 and January 5. In November, Yousif Attia, Birds Canada’s national CBC co-ordinator said “This upcoming season marks the 122nd year for the CBC in Canada. If you’re interested in birds and their conservation, I encourage you to participate, whether you’re a novice birder or a seasoned expert.”

This year’s London count is set for Saturday, December 18. London-based birding expert Pete Read, who has been the compiler for the London CBC since 1983, will again co-ordinate locally. For information about how to get involved in the London CBC, contact him at

During Christmas Birds Counts, experienced birders can be matched with new birders so that knowledge sharing can occur. Another aspect of the CBCs is feeder watching. This is especially good in the face of pandemic issues or especially heavy weather or for persons with mobility issues. Instead of hiking a designated route, feeder bird counts are completed for part of the day.

Through the past decade, the Christmas Bird Counts for kids, also known as CBC4Kids events, have been held in early December across Canada. This is a tremendous opportunity to introduce kids who are in grades 3 to 8 to bird watching and citizen science.

Nature London has hosted the CBC4Kids in London since 2014. This year’s version will occur from 9:00 to 10:30 a.m. on Saturday, December 4 at London’s Springbank Park. The event is open to the public and binoculars will be made available to participants who don’t have their own. Pre-registration is required and participants must be masked and accompanied by a fully-vaccinated adult. For information about registration and other details, visit the Nature London website.

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