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. 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 Centre 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.
The count circle is divided up and teams of birders are assigned to cover the different sub-areas. 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 . There is no restriction as to where a count may take place, except that no two-count circles may overlap. The Vancouver, Ladner and Victoria CBCs, at roughly 140 species each, have the distinction of consistently recording the highest number of species of any CBC in Canada.