Sandhill cranes have a long and vulnerable breeding season, according to Richardson. Their eggs incubate for about 30 days, and young sandhills don't learn how to fly until several months after birth.

Sandhill cranes fly to roost on March 10, 2021, in Monte Vista. More than 20,000 cranes spend part of their spring and fall each year in this valley as they migrate toward the north. (Photo by ...

Each year tens of thousands of sandhill cranes stop at a Minnesota wildlife refuge for an extended layover as part of their migration south. These birds are long-legged, loud -- and methodical.