Monday, November 28, 2005

Counting Birds

Every year, birders participate in a series of "citizen science" projects during the winter. Though participation probably skews towards more experienced and active birders, people of all age and skill levels are welcome to contribute. These projects help to add extra interest to birding during the winter months when birding otherwise slows down in most places - because of both the weather and the diversity of birds in the area. (One of the few exceptions is along the coast, but not all birders can get there easily or care to fight the wind.)

Two relatively recent developments are Project Feeder Watch and the Great Backyard Bird Count. These are sponsored jointly by the National Audubon Society and the Cornell Lab of Ornithology. Project Feeder Watch runs this winter from November 12 to sometime in April. (Yes, I am late posting about it!) Participants are asked to count the birds that visit their feeders on two days a week consistently over the course of the program. The Great Backyard Bird Count is a one-weekend event. In 2006 it is the weekend of February 17-20. Counters observe and report the types and numbers of birds they see in their selected counting area over the course of the weekend. This is similar to Project Feeder Watch in some ways, except that it provides a one-weekend snapshot of bird populations across the North America rather than a winter-long picture.

The oldest and most prominent of winter bird projects is the Christmas Bird Count. Christmas bird counts began as a non-lethal alternative to the competitive hunting that was common on Christmas at the turn of the twentieth century. Frank M. Chapman, a curator at the American Museum of Natural History in New York and one of the founders of the National Audubon Society, encouraged bird lovers to go out and count as many birds as they could find, instead of shooting them. Over time, these counts became more organized so that the Christmas bird counts so that they developed into a nationwide bird census.

This winter, the Christmas Bird Count period runs from December 14 to January 5. The three-week range of dates gives localities flexibility in planning them (and in providing alternate dates in case of bad weather). It also allows individual birders to participate in multiple counts. (Some people are gluttons for punishment. Ahem.)

In the Washington, D.C., area, there are multiple bird counts, one for each county. A list of counts in Maryland is available here. The District of Columbia count is on December 17. A list of the counts in Virginia can be found here. Once the CBC period is over, there are also some midwinter counts, listed here. One count focuses on the C&O Canal, and covers its 184.5 mile length in 3-4 mile segments. (Check the DC Audubon page for more details.)

What all of these projects have in common is that they attempt to measure the wintering population of each species across North America and in specific regions. While not a perfect census, the data gathered can be useful for establishing broad historical trends. We can see which species are declining, which are increasing, and how wintering ranges shift.