I've seen something very similar at Bosque del Apache here in New Mexico, where some of these birds winter. I was there on a cold January dusk as thousands of cranes came back to the safety of the water after a day foraging. An incredible sight with incredible sounds. Thanks for the video. It reminds me I should take another drive down that way this month or next. It's not uncommon to see a coyote, reminding you why the birds are standing in the water for the night.