The Great Backyard Bird Count is this weekend, February 12-15. This is a great activity for families and for classrooms. The four-day event gives a real-time snapshot of where birds are.
And it's simple, fun, and free. Just count the number of birds you see in a time period. How many cardinals are at the bird feeder in a fifteen minute time period? How many mourning doves are in your yard during the day? Are there any owls or woodpeckers or finches?
The following is copied from the official website for the event (http://www.birdsource.org/gbbc/howto.html)