"'Birds fly south in the winter.' 

It’s a phrase so familiar it feels like common sense. But the idea that birds migrate -- let alone where they go and how they get there -- is knowledge hard-won through decades of careful observation and scientific discovery. In the United States, much of what we know about bird movements, populations, and the health of our ecosystems comes from two foundational programs run by the U.S. Geological Survey (USGS): the Bird Banding Laboratory (BBL) and the North American Breeding Bird Survey (BBS). These programs don’t just tell us where birds go. They reveal how our environment is changing, which species are declining, and where conservation action is most needed —making clear that both programs merit our attention and support..."