Every spring and fall, the morning air fills with the ancient and primal call of the Sandhill Crane. The locals know that when they hear this sound in April, winter is gone. And when they hear it in September, winter is not far off. The cranes migrate along a corridor from Northern California to the Alaskan Arctic, stopping over for a day or a week or more at the same stopover points each year. Photographer: Sean Neilson