This video from the USA says about itself:
Flock of Sandhill Cranes
5 June 2015
One of two crane species in North America, and by far the most common and frequently encountered, the Sandhill Crane is a large, graceful, long-necked bird of open prairies and wetlands. This species gathers in large flocks outside of the breeding season, and the collective cacophony of their bugling calls can be deafening. Their large size, red crown, and slender black bill help distinguish the Sandhill Crane from any heron or egret species.