Every year volunteers throughout the western hemisphere take a census of birds within designated 15-mile diameter circles. The circle is divided into sections and surveyed by teams to identify and count all of the wild birds present. In addition to field teams, we have feeder watchers who identify and count the birds at their feeders. The results are tallied and submitted to the National Audubon Society. This data is compared with historical records to document changes in bird populations and used in multiple research projects like the State of the Birds and the Audubon's Birds and Climate Change Report.