Christmas Bird Counts are censuses of all birds (all individuals and all species) found in a defined area on a given count day. The count provides population data for use in research and conservation efforts. For more information about the Christmas Bird Count, visit the National Audubon Society’s CBC page.
Yosemite Area Audubon Society members and friends are enthusiastic participants in the Christmas Bird Counts each year. The counts are part of the National Audubon Society’s Christmas Bird Count, an annual avian census held between December 14 and January 5.
Begun on Christmas Day in 1900, this event is now the longest-running wildlife survey and the oldest citizen-science project in the world. Ornithologist Frank Chapman proposed this annual bird count as an alternative to the traditional “side-hunt,” a competition for hunters to shoot as many birds as they could kill on Christmas Day.
Chapman’s brainchild has grown from its original 25 locations, mostly in northeastern North America but including Pacific Grove in California, to more than 2,100 counts ranging from the Arctic to South America. Twenty-seven hearty souls participated in the first count; today volunteers number in the tens of thousands, all of them helping amass data that collectively inform scientists of bird population trends and patterns and, in turn, decisions by the agencies responsible for bird conservation.
Like all Christmas Bird Counts, each of the three local tallies (Mariposa, Yosemite, and Oakhurst) takes place within a fixed 15-mile-diameter circle established by the count originators. The compiler selects a date within the prescribed window of time for the count. On that one day participants, assigned to specific zones, fan out inside the circle to cover the area as widely as possible and to count all the birds observed and identified. At the end of the day the results are compiled for submittal to National Audubon.
National Audubon president and CEO David Yarnold has commented, “The Audubon Christmas Bird Count harnesses volunteer power to gather knowledge that shapes conservation policy at enormous scales in this country. I couldn’t be prouder of the 60,000-plus volunteers who contribute each year….”
Christmas bird counts are among a number of citizen-science projects that engage members of the Yosemite Area Audubon Society, the local chapter affiliate of the National Audubon Society and its state affiliate, Audubon California, in bird conservation and in habitat protection, restoration, and education. YAAS invites area residents to discover the fascination and fun of birding by attending its monthly programs, participating in monthly field trips and getting involved in some of its exciting projects.
Participation in all counts is free, and all are welcome regardless of birding experience.
Mariposa Count Circle
The count circle, ranging in elevation from less than 1,000′ to about 3,500′, mirrors the predominantly rural character of Mariposa County. About 30% of the area comprises large ranches of several hundred to upward of 1,000 acres, and national forests constitute about 20% of the area. An estimated 95% of the private properties within the circle are a minimum of 5 acres in size. Habitats include montane mixed-conifer/oak woodland dominated by ponderosa pine, incense-cedar, and California black oak (25%); blue oak/valley oak/live oak/foothill pine woodland sprinkled with grassy rangelands (40%); blue oak savanna (5%); chaparral with a mix of chamise, manzanita, scrub oak, and Ceanothus spp. (25%); and riparian (streams and ranch ponds bordered by willows, alders, cottonwoods, cattails, reeds, and many perennials) (5%). Shrubs and wildflowers of many species splatter all of these habitats. The mosaic of habitats and the biodiversity, particularly within the blue oak woodland, is acknowledged as one of the most biologically diverse and productive in California. The diversity and abundance of birds consistently produce significant numbers of species and individuals within the circle area.
Oakhurst Count Circle
2011 was the first year that the Oakhurst Count Circle was included as an approved circle.
Neighboring Count Circles
Other official CBC circles in our area include Yosemite, Groveland, and Merced.