There are probably 40,000 to 50,000 people in the U.S. who are.... It varies from year to year how many people are actually participating in the Christmas bird count, but there are roughly 2,500 or 3,000 compilers—the ones in charge of the counts—plus 70,000 to 80,000 observers. We also have a team of regional editors, getting to the accuracy point, who review all the data from every count submitted before it is actually finalized for a given season. That's all volunteer work.
