POSTED // Mar 11,2014 - This great influx of birds can start at any time between February and early March. It’s as if from hundreds of miles away, the swans feel the thawing of ice in this little valley and begin to fly north. As the melt starts, they appear. At first, they come in the hundreds, then the thousands. At the migration’s peak, tens of thousands of white tundra swans descend, covering the water, the land, the air.