How the League Works: County Divisions are updated from eBird manually as recent as possible when time allows. By grouping counties in Division with similar annual species counts, using their Last 10 Years data, so that each division has a relatively level competitive field
Promotion and Relegation: Each year, the divisions are recalibrated to reflect changes in Last 10 Years averages. So, at the conclusion of each year, some counties may earn Promotion to the Division above, or may face Relegation to the Division below.