The Christmas Bird Count is the oldest continually running citizen science project about birds in America. It all began on Christmas Day, 1900, from the suggestion of ornithologist Frank Chapman, an early officer of the new Audubon Societies. Conservationists were growing increasingly concerned about the decline in bird populations and game species. The new tradition was a "Christmas Bird Census" that would count birds during holidays rather than shoot them. It started very modestly with only 27 count areas in the country, including 5 in Pennsylvania, but now spans across the North American continent and into Latin America. The CBC is a tradition now and a great way to involve new birders in a bird science project.
The CBC has grown remarkably in geographical scope and participation. There now are many CBC circles in Central America that document not only the regional residents, but the many birds that nest in North America and winter in Latin America and the Caribbean region. Now there is even a CBC in Antarctica. Pennsylvanians can participate in counts close to home and far away, having fun and making a contribu-tion to our knowledge of birds along the way.
What? The CBC is a survey of bird populations in early winter. It is done using established "count circles" that are surveyed each year by the same local bird club or Audubon chapter. Each circle has a Count Compiler that organizes the local effort. Please visit the National Audubon Society's website and especially its CBC FAQs to learn more.
When? The CBC season is December 14 through January 5 each year. Each local count will occur on one full day between these inclusive dates. Usually, nearby counts are on different dates to allow birders to participate in multiple count circles. Each count coordinator selects the date for the local circle's count and announces this information to the birding public.
Who? A wide variety of birders can be involved, beginners to advanced. The CBC is an opportunity for beginners to engage in a bird-counting project where they can be involved with a group that includes at least one experienced birder and learn from that person. People can participate by spending many hours in the field or by being a feeder watcher. There are a variety of ways to be involved. There is no longer a $5 fee to participate in the CBC for all field participants aged 19 or older.
Where? The CBC focuses on specific geographical areas called "count circles." For the 2000-01 season, there were 1714 count circles in the United States, 70 in Pennsylvania, and 2160 world-wide. Each count circle has a 15-mile diameter with a well-established center point. This allows year-to-year comparison of data for comparisons between years and count areas. If you have never been on a CBC before, your first step is to locate and contact your local Count Compiler to find out how you can volunteer.
How? Individuals are assigned to part of the local CBC count circle working as a team with other participants. Each group identifies and counts all birds encountered, making sure that birds are not double-counted by each party or multiple parties. Participants also keep tabs on time and distance traveled.
CBC can be a very active birding project. It is common to drive a vehicle along the roads of the CBC area, but many participants get out and walk. If it is snowy, some participants have used cross-country skis or snowshoes to get out there and find birds. The count benefits from scouting the area ahead of time and learning the hotspots that seem to change each year. For more tips about making a CBC more successful see the article about CBC tips.
Get Involved: Contact your local CBC coordinator. A list of CBC coordinators is available at the National Audubon Society website and also in the late fall edition of The Pileated, the quarterly newsletter of the Pennsylvania Society for Ornithology. Invite others to help with the local Christmas count especially those that are just starting out.
Benefits: The CBC has been an important bird science project for more than100 years. One of its benefits is in the involvement of thousands of individuals in bird counting, recruiting many new people to bird watching and scientific pursuits. There is an annual summary of the CBC data in a volume of "American Birds." The Pennsylvania CBC data are summarized in the PSO publication "Pennsylvania Birds." Many scientific publications have used CBC data. It has been very useful to track the change in populations and ranges of many bird species.
The CBC has been a great way to track changes in winter ranges of birds due to changes in weather and habitat. "Irruptions" of birds, the movements of large numbers of individuals from their usual non-breeding range, also are well-documented by CBC data. This includes many seed-eating birds, especially those that forage mostly on conifer seeds. It also includes raptors that prey on small rodents in open fields that tend to travel south during certain conditions.
Species of conservation concern are well-tracked by the CBC. Since many birds nest in the remote north where counting birds is very difficult, these species are easier to count on their winter ground. So, many of the boreal species are monitored best by the CBC. For instance, the CBC has been the primary survey documenting the drastic decline of the wetland songbird, Rusty Blackbird, and also helps identify the species' key wintering regions.