With the arrival of meteorological spring - March 1st - new bird activity is showing up in the Upper Mississippi River region. Meteorological seasons, which begin on the first day of the months rather than the third week, are determined by annual temperature cycles rather than sun angle. As a birder here in the north, this seasonal designation makes sense to me. The spring months of March - May are when new birds are arriving and setting up their territories. The summer season of June - August is the nesting and fledging time. September - November is the season that encompasses all the southerly migrations of different species that occur a various times throughout the time period. And December - February are the quiet months with our winter “local” birds and hopefully a species or two migrating south from Canada or a few species staying north of their usual range. Many species will already be migrating through by the time this year’s astronomical spring equinox arrives on March 20th.