Snowy Owls lead nomadic lives and travel vast distances from year to year searching for productive feeding areas. Some years, most recently in the winter of 2011/2012, conditions cause them to come south in great numbers.
For a short video on the Snowy Owl Invasion see: http://www.youtube.com/watch?v=Ufkcx-UqljM&feature=player_embedded
For a short video on the Snowy Owl Invasion see: http://www.youtube.com/watch?v=Ufkcx-UqljM&feature=player_embedded