Each year, humans also flock to nature preserves in the region to witness the spectacular sight of sandhill cranes congregating in large numbers, including Sherburne National Wildlife Refuge in Minnesota and Crex Meadows State Wildlife Area in Grantsburg, Wisconsin.
Our volunteer photographer Lorie Shaull recently traveled just over the state line to see the crane convention for herself, capturing beautiful images and video of the creatures.
Lauren Thomas is a natural resources educator with the Wisconsin Department of Natural Resources who is based primarily out of Crex Meadows. She shared some of her favorite crane facts, the mysteries behind the mass migration and what visitors can expect, should they wish to see it for themselves.
Thomas said for the past couple of million years, sandhill crane anatomy hasn't changed much, which is why some people call them a living fossil.
"It's really cool that these birds have been able to kind of survive and thrive without having to adapt a whole lot, and it's something that we can see in a lot of their behavior," she said.
"Just for an example, sandhill cranes are a generalist species in their feeding behavior, and so they'll eat a very wide variety of things in their diet. And so it's something that helps them in the long run, as they don't have to compete directly with a lot of other species."
As for why the cranes follow such a strict migration path year after year, Thomas explained that bird migration is a topic scientists still don't know a lot about. But they have been able to learn some from watching birds and examining their behavior.
"To help navigate along the migration route, one of the things that they are looking for are things like landforms that will help them to navigate down to these areas. They might follow along the path of a river, so like in our area we'd be talking about the Mississippi," she said. "But there are some other things to be said too, about why the sandhill cranes would choose Crex Meadows to congregate."
Thomas said the 30,000-acre wildlife area provides a large area of suitable habitat and feeding opportunities, namely surrounding agricultural fields where cranes often feed in the fall.
Sandhill cranes congregate in shallow water in the evenings and roost in large numbers overnight. The large birds preparing to settle in for the night is what visitors come to witness at places like Crex Meadows.
"They will all fly in in the evening, so really really loud when they fly in over the road, and they're they're calling back and forth to one another and oftentimes they'll land — in some locations — really close to the road," she said.
"And so that is the time that people will want to be viewing the cranes, and typically that happens couple of hours or so before it gets dark."
