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  If you would like to participate, please contact Frank DeMartino at  




The data collected by observers over the past century allow Audubon researchers, conservation biologists, wildlife agencies, and other interested individuals to study the long-term health and status of bird populations across North America. When combined with other surveys, it provides a picture of how the continent's bird populations have changed in time and space over the past hundred years.

How the Christmas Bird Count Works

Each individual count is performed in a "count circle" with a diameter of 15 miles (24 kilometres). See the interactive map below for all count circles.  The Count Compiler coordinates the count, and for Ventura Audubon our count compiler is Frank DeMartino.  


Each circle is subdivided into sectors, and each sector has a leader who reports their count results to the compiler. The compiler uploads the final count data to the Audubon National database. Volunteers work under the direction of the sector leaders.  Some sector leaders are veterans who have lead the same sector for decades, other sectors need new leaders.  The same is true for volunteers, with both long time veterans and needs for new counters. We will typically recruit someone who has counted the sector before as a volunteer to be a new leader.


So the count compiler works hard to make sure each sector is covered and counted.  We need our veteran counters and skilled birders, but there is also room for new and intermediate birders as well as volunteers new to Audubon. 


If you would like to volunteer or need to find an opening in a new sector, contact our compiler Frank (email) and he'll find a place for you in our count circle! We can also use data from backyard counters!!

VAS CBC circle.jpg
Ventura Audubon Society CBC Count Circle

Our December speaker program is all about the Christmas Bird Count, so please join us if you would like to learn about the history of the count, how you can participate as volunteer or backyard birder and our most wanted CBC birds!

Interactive map of all 2022 CBC Count Circles

Prior to the turn of the 20th century, hunters engaged in a holiday tradition known as the Christmas "Side Hunt." They would choose sides and go afield with their guns—whoever brought in the biggest pile of feathered (and furred) quarry won. Conservation was in its beginning stages in that era, and many observers and scientists were becoming concerned about declining bird populations. Beginning on Christmas Day 1900, ornithologist Frank M. Chapman, an early officer in the then-nascent Audubon Society, proposed a new holiday tradition—a "Christmas Bird Census" that would count birds during the holidays rather than hunt them.


So began the Christmas Bird Count. Thanks to the inspiration of Chapman and the enthusiasm of 27 dedicated birders, 25 Christmas Bird Counts were held that day. The locations ranged from Toronto, Ontario to Pacific Grove, California with most counts in or near the population centers of northeastern North America. Those original 27 Christmas Bird Counters tallied around 90 species on all the counts combined. 


Each November, birders interesting in participating in the CBC can sign up and join in through the Audubon website. From December 14 through January 5 each year tens of thousands of volunteers throughout the Americas brave snow, wind, or rain, and take part in the effort. Audubon and other organizations use data collected in this long-running wildlife census to assess the health of bird populations, and to help guide conservation action. The long term perspective is vital for conservationists. It informs strategies to protect birds and their habitat, and helps identify environmental issues with implications for people as well. 


Audubon’s 2014 Climate Change Report is a comprehensive, first-of-its kind study that predicts how climate change could affect the ranges of 588 North American birds. Of the 588 North American bird species Audubon studied, more than half are likely to be in trouble. Our models indicate that 314 species will lose more than 50 percent of their current climatic range by 2080.

The Environmental Protection Agency (EPA) has included Audubon's climate change work from CBC data as one of 26 indicators of climate change in their 2012 report.

In 2009 CBC data were instrumental in the collaborative report by the North American Bird Conservation Initiative, U.S. Fish & Wildlife Service - State of the Birds 2009

In 2007, CBC data were instrumental in the development of Audubon’s Common Birds in Decline Report, which revealed that some of America's most beloved and familiar birds have taken a nosedive over the past forty years.



During the 18 years that Karl Krause served as Compiler for the Ventura Audubon CBC, he collected and documented an excellent history of the bird count data.  He expanded the database to include more limited data from the earliest VAS CBC in 1980.  Brad Sillasen believed it would be very interesting to publish these trends in local bird populations and to make the information available on the web.  After all this is the point of the counts. 


Using Karl Krauses’ data Brad developed a wonderful interactive application that clearly shows the trends in bird populations within Ventura Audubon’s Count Circle.  The “count circle” is a 15-mile diameter circle centered, approximately, on Cañada Larga Road.  Every year, the count is conducted within the same circle that is divided into eight sectors.  

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