The Christmas Bird Count?
The oldest North American birding tradition is the annual census of winter bird populations, known as the Christmas Bird Count (CBC). In the late nineteenth century, for Yuletide amusement, hunters would have contests to see who could shoot the greatest number of birds. One of the leading ornithologists of the day, The American Museum of Natural History’s Frank M. Chapman, was so horrified by the practice of the Christmas hunt, that he decided to organize groups of conservationists to go out and count birds instead.
The first few counts, conducted in 1900 by 27 participants, evolved into the largest and longest running wildlife survey in history. Today, approximately 1,700 CBCs are conducted by an estimated 45,000 participants in Canada, the U.S.A., Central and South America, and some of the Caribbean and Pacific islands. 97% of these counts are in Canada and the U.S.A. covering about 4.5% of the landmass north of Mexico. All of the data collected is compiled, stored and made available to the scientific community by the National Audubon Society and its headquarters in New York City and the Patuxent Wildlife Research Center in Laurel, Maryland. The longevity of the CBC database has made it a valuable tool for gaining critical insights into the long-term health and changes to wild bird populations and the environment as a whole. Many conservation and wildlife management groups use the data including the Canadian Wildlife Service and the U.S. Fish and Wildlife Service.
As many of the early counts were haphazard affairs, the Audubon Society decided, in the 1950s, to standardize the methodology of conducting a CBC, and today, all counts follow this set of guidelines. Consistency is crucial for the meaningfulness of any database. Organizers of a CBC for a particular area will decide on a geographic point as the centre of the count area, and the census takes place on a single day in a 7.5 mile radius (12.06975 km for us birders in Canada) from that point. This area, known as the “count circle”, covers an area of approximately 177 square miles (458 sq. km). The count circle is divided up and teams of birders are assigned to cover the different sub-areas. Participation is open to all (to defray the cost of organizing the count and publishing the results there is usually a nominal fee for participation) so the organizer will usually ensure that novice birders are teamed up with more seasoned count participants. The team is responsible to record both the number of species and number of individual birds seen and heard in their area.
All participants meet at the end of the day to hand over the data to the organizer, who then compiles the information into a master list and forwards it to the Audubon Society. Although the census takes place on one day, organizers may choose any day within the count period, from Dec. 14th to Jan. 5th inclusive. There is no restriction as to where a count may take place, except that no two-count circles may overlap. Count locations tend to be concentrated near urban and suburban areas (because that’s where the birders are) or in areas of known winter concentrations of birds.
With the mildest winter climate in Canada, and a wide variety of habitats in a small area, counts in the southwest coast of British Columbia (particularly the Vancouver, Ladner and Victoria counts) consistently produce the highest number of species of all CBCs in the country. The current Canadian record for number of species on a single count is 152, shared by Victoria (1991) and Ladner (2001). For more information on CBCs in your area contact any one of the naturalist clubs mentioned in the “Clubs & Publications” section of this booklet or visit the Audubon Society’s CBC webpages at www.audubon.org/bird/cbc/.