The Christmas Bird Count is an annual bird census organized by the National Audubon Society to assess the health of bird populations. Volunteers across North America take part in the effort each year between December 14 and January 5. The Christmas Bird Count provides critical data on bird population trends and is the longest running wildlife census in the world.
When did the Christmas Bird Count start?
The Christmas Bird Count began in 1900 as an alternative to the holiday tradition of hunting birds. Prior to 1900, people would participate in a Christmas “side hunt” where teams competed to see who could shoot the most birds and small mammals on Christmas Day. Conservationist Frank M. Chapman proposed counting birds instead of hunting them, leading to the first Christmas Bird Count organized by 27 volunteers in 25 locations across North America.
How does the Christmas Bird Count work?
The Christmas Bird Count is conducted by volunteers within established 15-mile diameter circles across the Western Hemisphere. Each count circle is organized by a compiler who recruits volunteers, coordinates logistics, and submits the data to Audubon. Volunteers follow specified routes through the count circle, counting every bird they see or hear all day. Experienced birders often lead groups of volunteers to ensure proper bird identification.
To be included, birds must be within the 15-mile diameter count circle and counted on 1 of the official count days. Birds seen during count week, the 3 days before and after the count day, are reported separately. The compiled counts provide researchers, conservation biologists, and other interested individuals with an enormous amount of data about early-winter bird populations across the Western Hemisphere.
How many Christmas Bird Counts are there?
There are over 2,600 Christmas Bird Count circles across North America, Latin America, the Caribbean and the Pacific islands. Last year, 2,120 count circles submitted data with 81,305 field observers counting 59,242,067 individual birds of 2673 species.
The number of count circles and participants has steadily increased over time. Below is a table showing the growth of the Christmas Bird Count from 1900 to 2020:
| Year | Number of Counts | Number of Participants |
|---|---|---|
| 1900 | 25 | 27 |
| 1920 | 88 | N/A |
| 1940 | 191 | N/A |
| 1960 | 1118 | N/A |
| 1980 | 1130 | 32,818 |
| 2000 | 1746 | 52,722 |
| 2020 | 2120 | 81,305 |
What do volunteers do during the bird count?
Volunteers are organized into groups that cover specified areas within the 15-mile diameter circle. Groups follow planned routes through their area, stopping at intervals to count birds. Some volunteers are assigned to stationary surveys at bird feeders or water sources. The most skilled birders are often leaders identifying species as flocks pass by. Other volunteers document the numbers and species being called out by the birding experts.
Volunteers count all birds seen or heard within their assigned area during the 24-hour period on 1 of the count days. The stationary counts at feeders and water sources are usually conducted for a shorter specified time, such as 2 hours. At the end of the day, group leaders submit their group’s species tally to the count compiler.
How are the results compiled?
Compilers gather the results from all the groups surveying areas within their count circle. The total species tally and number of individuals of each species are compiled for the entire count circle. Compilers submit the count circle results through Audubon’s online portal by January 31st of each year.
In addition to the 1-day count totals, compilers also document birds observed during “count week,” the 3 days before and after the formal count day. While included in the historical record, count week birds are analyzed separately from the official 1-day count totals.
How are Christmas Bird Count results used?
The Christmas Bird Count provides critical long-term data on early winter bird populations across the Americas. Scientists and conservationists use the count data to study the health of bird populations. By documenting the fluctuation in populations over time, researchers can identify species in decline and determine patterns and causes of decline.
Below are some key examples of how Christmas Bird Count data aids conservation:
- Documents impact of habitat loss and degradation on bird species
- Identifies bird populations requiring conservation action
- Provides insight into effects of climate change and shifts in bird ranges
- Establishes baseline for comparing effectiveness of conservation actions
- Educates and engages citizens in bird conservation
The long-term dataset generated by the Christmas Bird Count is more vital than ever for understanding changes in bird populations. Audubon and other organizations use the data to assess the conservation status of birds and guide efforts to protect species and habitats.
How has the Christmas Bird Count data been used for specific conservation issues?
Understanding Declines in Grassland Birds
Christmas Bird Count data combined with results from Audubon’s Breeding Bird Survey have been instrumental in documenting declines in grassland bird species. Birds such as Grasshopper Sparrow, Eastern Meadowlark, and Bobolink have declined by as much as 90% in some regions as grasslands are converted to agriculture or developed. Christmas Bird Count data has helped researchers understand these declines and identify priority areas for grassland conservation.
Tracking Range Changes of Birds
By examining long-term Christmas Bird Count data, researchers have been able to document range shifts of bird species, particularly those driven by climate change. As temperatures increase, many bird species are shifting poleward and to higher elevations. The declines of species like the Common Nighthawk in the southern parts of their ranges have been detected through the Christmas Bird Count.
Identifying High-Priority Areas for Conservation
Areas that support high numbers of threatened species can be identified through the Christmas Bird Count. This allows conservation groups to target vital habitats and work with governments and landowners on conservation efforts. For example, Important Bird Areas have been designated across the Americas based in part on Christmas Bird Count data.
Tracking Success of Conservation Measures
Because the Christmas Bird Count provides such a long historical record, it is invaluable for determining if conservation actions are having the intended impact. For example, Christmas Bird Count data showed that wetland restoration efforts slowed declines and resulted in increases in waterfowl populations in many areas of North America.
What are some notable Christmas Bird Count milestones?
- 1949 – First international count circles established in Canada, Bermuda and the Pacific islands
- 1955 – 100,000th individual count conducted
- 1972 – 100th year of the Christmas Bird Count
- 2012 – Record high number of circles conducted in 2,369 locations
- 2018 – 60 million individual bird count milestone reached
How can I participate in the Christmas Bird Count?
New volunteers are welcome to join the Christmas Bird Count! The first step is finding a local count circle near you by using Audubon’s circle finder tool. Reach out to the count compiler to find out details about the specific count and how to take part. First-time participants will join an existing group to learn the ropes from more experienced birders.
The Christmas Bird Count is free and open to birders of all skill levels. Beginners are welcome to join and learn about birds alongside seasoned birdwatchers. All that is needed is a passion for birds and the outdoors! Participating in the Christmas Bird Count is both fun and meaningful by contributing to the protection of birds.
Conclusion
For over a century, the data generated by the Christmas Bird Count has informed conservation efforts and advanced our understanding of bird populations. From its humble roots with 27 volunteers in 25 locations in 1900, the Christmas Bird Count has grown into one of the longest running wildlife censuses in the world. Each year, tens of thousands of volunteers brave winter weather to contribute vital data on the health and range of bird species across the Western Hemisphere. The Christmas Bird Count continues to provide critical long-term data to assess bird populations, identify species in decline, and inform conservation actions to protect birds and their habitats.
