Davis talks hopefully of the mussels returning when people start treating rivers with a little more wisdom and sensitivity. Those sorts of improvements have brought dramatic returns to parts of Minnesota for pelicans and tundra swans, which draw tourists and help local economies.

“I don’t know how many people we’re going to get to watch the mussels,” he said. “I keep talking them up.”

Joyce Reese is hooked after one look.

“This was the first time I ever walked the river and it was wonderful,” said Reese, of Lafayette, who brought along cousins George Hartley, 10, and Matthew Hartley, 9.

They were captivated, too, as they held a muddy rock that had slimy little blobs attached to it that Davis guessed were snail eggs. They planned to take it home, along with some Cottonwood River water, and see what the blobs turn into.

Soaked from the knees down, they talked about what they’d seen in a span of time where many of their peers had seen nothing other than three Saturday-morning cartoons.

“I saw lots of minnows and some crawfish,” said Matthew, who also found a bone in the riverbed that was shaped like a duck’s beak.

“Dragonflies and dragonfly nymphs,” George said, adding to the list. “And lots of clams.”