A like totally cool site, BirdCast, from the Cornell Lab of Ornithology.
We take the fall and spring migrations for granted, but they are in fact miraculous feats and remarkable adaptations to the climate changes of the ice age era (which we are still in today - and have been for 2.6 million years with lulls and expansions of northern hemisphere ice. If you can apply "normal," this planet normally has no ice).