This weekend marks the annual Great Backyard Bird Count (GBBC), a four-day event that makes “citizen scientists” out of bird watchers and nature lovers across North America. The campaign is part of a broad effort to keep tabs on the continent’s bird populations, using volunteers of all ages and backgrounds to supplement more formal research.

https://www.mnn.com/earth-matters/animals/blogs/2012-great-backyard-bird-count-takes-flight