Christmas Bird Count

The Christmas Bird Count (CBC) is a long-standing program of the National Audubon Society, with over 100 years of citizen science involvement. It is an early-winter bird census, where thousands of volunteers across the US, Canada and many countries in the Western Hemisphere, go out over a 24 hour period to count birds. It was started by Frank Chapman, along with 26 other conservationists, as a way of promoting conservation by counting, rather than hunting, birds on Christmas Day of 1900.

About CBC

The Christmas Bird Count (CBC) was formally launched by the Audubon Society in 1900 when 25 surveys were conducted in the U.S. and Canada. Today there are approximately 2100 active CBC circles across the US, Canada and several Latin American and Caribbean countries. Christmas Bird Counts are conducted during the peak of winter, between December 14 and January 5. Counts of all birds seen and heard are made within 15-mile (24 kilometer) diameter circles for 8-12 hours on one day by multiple volunteer observers.

Official CBC Website

Acquiring CBC

The full CBC database is currently only available via MOU with Audubon. Small queries can be executed through Audubon's websites, but an MOU may still be necessary for publication based on these data. See this page for more information about proper citation information, contact information, and papers that have used the CBC data.

Using CBC

http://birds.audubon.org/historical-results

Database structure notes

• Count year data are in SUB_AUX table, which is linked to the OBS table via SUB_ID
• Site codes (LOC_ID) are in the SUB table, which is also linked to the OBS table via SUB_ID

Best practices

• Exclude nocturnal, crepuscular, and aquatic species as they are not well sampled
• Remove species with HOW_MANY = 0 if a species list is desired
• Strongly consider making inferences on species primarily dwelling in urban areas
• Sampling effort (party hours) is often incorporated into abundances by dividing #birds by #party hours