Twice a year, every birder who is able to do so heads out into the field to take a count of every bird they see in their assigned territory. These events are scheduled during spring and fall migrations, so they are called, naturally enough, the Spring North American Migration Count (NAMC) and the Fall NAMC (this link will expire by the time the Spring 2010 count rolls around).
Wait a minute. All the birders in an area going out and counting all the birds they see? Doesn’t that sound a lot like the Christmas Bird Count? It might sound like it, but it really isn’t the same thing at all. The more famous, to nonbirders, Christmas Bird Count, has a similar goal–get all the birders in an area out and counting–but uses a different method. In the CBC, one has a count circle of 15 miles radius, and one counts all the birds one sees in that circle. That provides excellent coverage, but one can’t cover all of Palm Beach County (area approximately 2600 square miles) with a circle that’s only 706.86 square miles (pi r squared, right?).
Another drawback to the CBC is that one records only the rare overwintering migrant. This continent is home to billions of birds on a summer-only basis, and there’s a good chance that we can count at least some of them on their passage through in spring or fall. In the dead of winter, even in a moderate climate like South Florida’s, it’s a lot harder to do that.
This Saturday, September 19, we will be out there, looking.