The Christmas Bird Count (CBC) is a census of
bird Birds are a group of warm-blooded vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With ...

s in the Western Hemisphere, performed annually in the early Northern-hemisphere winter by volunteer
birdwatchers ''BirdWatchers'' ( it, La terra degli uomini rossi) is a 2008 Brazilian-Italian drama film directed by Marco Bechis and starring Claudio Santamaria, Alicélia Batista Cabreira, and Chiara Caselli. It depicts the breakdown of a community of Guaran ...
and administered by the
National Audubon Society Audubon may refer to: People * John James Audubon John James Audubon (born Jean-Jacques Rabin; April 26, 1785 – January 27, 1851) was an American ornithology, ornithologist, natural history, naturalist, and Painting, painter. His combin ...
. The purpose is to provide population data for use in science, especially
conservation biology Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an int ...
, though many people participate for recreation. The CBC is the longest-running
citizen science Citizen science (CS; also known as community science, crowd science, crowd-sourced science, civic science, or volunteer monitoring) is scientific research conducted, in whole or in part, by amateur (or nonprofessional) scientists. Citizen scienc ...
survey in the world.


Up through the 19th century, many
North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...

North America
ns participated in the tradition of
Christmas Christmas is an annual festival commemorating Nativity of Jesus, the birth of Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people Observance of Christmas by country, around the world ...

"side hunts", in which they competed at how many birds they could kill, regardless of whether they had any use for the carcasses and of whether the birds were beneficial, beautiful, or rare. In December 1900, the U.S. ornithologist Frank Chapman, founder of Bird-Lore (which became Audubon magazine), proposed counting birds on Christmas instead of killing them. On Christmas Day of that year, 27 observers took part in the first count in 25 places in the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

United States
Canada Canada is a country in the northern part of North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean, Atlantic to the Pacific Ocean, Pacific and northward into the Arctic Oce ...

, the count totaling 18,500 individual birds belonging to 90 species. Since then the counts have been held every winter, usually with increasing numbers of observers. For instance, the 101st count, in the winter of 2000–2001, involved 52,471 people in 1,823 places in 17 countries (but mostly in the U.S. and Canada). During the 113th count (winter 2012–2013), 71,531 people participated in 2,369 locations. The National Audubon Society now partners with
Bird Studies Canada Birds Canada (formerly Bird Studies Canada) is Canada's national bird Conservation movement, conservation organization. Birds Canada began as the ''Long Point Bird Observatory'' in 1960, changing its name in 1998 to reflect the growing national s ...
, the Gulf Coast Bird Observatory of
Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, ...

(responsible for CBCs in
Mexico Mexico, officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the south and west by the Pacific Ocean; to ...

), and the Red Nacional de Observadores de Aves (RNOA, National Network of Bird Observers) and the Instituto Alexander von Humboldt of
Colombia Colombia ( , ; ), officially the Republic of Colombia, is a transcontinental country This is a list of countries located on more than one continent A continent is one of several large landmasses. Generally identified by conv ...

. The greatest number of bird species ever reported by any U.S. location in a single count is 250, observed on December 19, 2005 in the Matagorda County-Mad Island Marsh count circle around Matagorda and
Palacios, Texas Palacios ( ) is a city in Matagorda County, Texas, Matagorda County, Texas, United States. The population was 4,718 at the 2010 census. Etymology Popular local legend states that the area was named Tres Palacios ("Three Palaces") several centuries ...
. The greatest number of bird species ever reported by a CBC circle in the world is 531, observed on December 21, 2013 in the Cosanga-Narupa count (previously known as the Yanayacu count) on the eastern slope of the Andes in Ecuador.


Participation in the Count is open to all, and as of 2012 participation was free of charge. Each individual count is performed in a "count circle" with a diameter of 15 miles (24.14 kilometres). At least ten volunteers, including a compiler to manage things, count in each circle. They break up into small parties and follow assigned routes, which change little from year to year, counting every bird they see. In most count circles, some people also watch feeders instead of following routes. Counts can be held on any day from December 14 to January 5 inclusive. The results are by no means as accurate as a human census. The experience of the observing birders influences both species identification and quality of locations examined. Not all the area in the count circles is covered, and not every bird along the routes is seen or identified. Big flocks can't be counted precisely. Also, telling whether a bird has been counted twice can be difficult. The rules address this problem by prohibiting counting birds when retracing one's route, except for species that the party hasn't seen before. Also, when a large roost of some species occurs in a count circle, an expert estimates the number for that species during the morning or evening and usually no individuals are counted at other times. Observers can attempt to keep track of flocks of mobile birds such as crows, and can use their judgement, even sometimes recognizing an individual bird or at least that two birds of the same species are different individuals. The results, providing data on winter ranges of birds, are complementary to those of the Breeding Bird Surveys.

See also

* Australian Bird Count (ABC) * BioBlitz ("24-hour inventory") * Breeding Bird Survey * Tucson Bird Count (TBC) (in Arizona in the US) *
Citizen Science Citizen science (CS; also known as community science, crowd science, crowd-sourced science, civic science, or volunteer monitoring) is scientific research conducted, in whole or in part, by amateur (or nonprofessional) scientists. Citizen scienc ...


Further reading

* {{Cite news, url=https://www.newspapers.com/clip/23148413/bird_count_more_than_just_game/, title=Bird count more than just a game, last=Richman, first=Talia, date=January 1, 2018, work=The Baltimore Sun, access-date=August 26, 2018, pages=1, 9, via=Newspapers.com Page 9 content located at https://www.newspapers.com/clip/23180435/christmas_bird_count_more_than_game_pt2/ .

External links

Audubon Official CBC page
(in Spanish) Bird censuses Ornithological citizen science