This is part of the larger Audubon Christmas Bird Count which runs from mid December to January every year (check their site for specific dates).
You can count birds in one of the areas noted on the map – if you want to include at-home feeder counts, you must ensure that your feeder is within one of their areas noted on the map.
It’s a free event, but they ask for a $5 donation.
Registration opens on November 1. Beginners are encouraged to participate, but they stress that it’s important to have an expert on your team to ensure a valid count.