Slow day today. I'm a little under the weather. So, here is an interesting (and short) video that recounts how mankind went from wondering where birds went in the winter to having a pretty good clue where they are all the time. There's new (or at least new to me) information in here, and I watch a lot of nature videos, so perhaps you'll enjoy it, too.
(With the cold we're having here in Chicago right now, I might have to fly south).