When Minnesota's bald eagles head south for the winter, they don't go far. Like the hardy Northerners they are, they're content to bask in the less-than-balmy breezes along the Mississippi River in southeastern Minnesota, which on the day these photos were taken had cooled the air, already struggling to reach zero degrees, to a 20-below windchill.

Birds don't migrate for warmth but for food, said Scott Mehus, education director of the National Eagle Center in Wabasha, Minn. And eagles from northern Minnesota, as well as Wisconsin and even Canada, head toward stretches of open water on the river to enjoy what Mehus calls a "floating buffet line."

It's a buffet of eagle-style sushi: dead fish that float down the Mississippi under the ice and then bob to the surface of a 5-mile stretch of water that always stays open. The main course is tiny gizzard shad — fish "so small you can hardly see them," Mehus said. "The eagles grab them with their feet and eat them on the fly."

Thanks to a blood-chilling mechanism involving the veins in their feet, eagles don't mind standing for hours on the edge of ice, peering into the water for these tidbits.

Still, Mehus noted, "everybody likes fresh fish" now and then. In winter, eagles get theirs by harassing ducks that dive underwater for live fish. It's basically a mugging; eagles have been known to eat actual ducks, so the ducks are pretty quick to hand over their catches instead.

Eagles can be spotted along the river from Red Wing, where these photos were taken, on south. Reads Landing near Wabasha is a particularly good viewing area, some days drawing hundreds of eagles, Mehus said. Even slower days bring 10 or 20.

He's especially grateful for their presence considering how close they came to disappearing altogether.

In the early 1960s, the population of bald eagles in the Lower 48 states had dwindled alarmingly. By 1968, only one nesting pair remained along more than 300 miles of river from Red Wing to Rock Island, Ill.

"We came very close to losing this bird, this magnificent symbol of our country," Mehus said.

The culprit? DDT, Mehus said. The then-popular insecticide kills bugs but then climbs the food chain; when it gets to eagles it weakens the shells of their eggs. Mother and father eagles would sit on the eggs (eagles share this parenting duty) and inadvertently crush their offspring.

DDT was banned in 1972. By 2007, the bald eagle came off the endangered species list. Nesting pairs in the Lower 48 states have climbed from 417 in the 1960s to over 10,000.

Minnesota leads with 2,300. As for the stretch of river that once held only one nest, Mehus said, "you could safely say there are over 350 on that same stretch today." □

Katy Read • 612-673-4583