Why do birds migrate?
November 16, 2011 7:46 PM Subscribe
Why do birds migrate to the Arctic and Antarctic?
I've been watching Frozen Planet and during the summer there is this huge explosion of life and all sorts of sea birds and what not migrate to the poles. Truly spectacular in HD, but I can't help but wonder: Given how much work it takes just to get there, well, why do birds bother?
Or to make my question sound more science-y: what is/was the selective pressure that drove various sorts of sea birds to begin these large migratory patterns in the first place?