Wildlife of the Middle Mississippi: Three Rivers, Endless Wonder

Somewhere between St. Louis and Cairo, Illinois, three of North America's largest rivers collide. The Mississippi, the Missouri, and the Ohio converge in a 200-mile stretch geologists call the Middle Mississippi. No dams. No locks. Just water doing exactly what water wants to do, and the animals that have learned to thrive in its unpredictable embrace.

This stretch draws wildlife the way a city draws people. The soil is soft, the grasses provide food, and the trees offer shelter from spring storms and summer floods. Conservationists have been building nest boxes here for nearly a century, hoping to give some species a fighting chance against modern pressures.

A Mother's Work

Spring arrives with complications. Red fox pups tumble around a den carved into the riverbank, but their mother carries more than her share of worry. Her coat is patchy from mange, a skin disease caused by mites that weaken her immune system. Her partner has grown distant now that the pups demand less vigilance, leaving her to raise the litter alone.

One of the kits got a stick in the eye. He will recover, but only because Mom keeps bringing scraps to the den. In six more months, these young foxes will leave to find territories of their own. Red foxes roam more of the planet than any other canine species, but this stretch of the Middle Mississippi is home in a way that nowhere else quite matches.

The First Leap

In a hollow tree, a wood duck mother has made a bed of her own feathers for a fragile clutch of eggs. When the last hatchling breaks free, the clock starts ticking. There is no food in the nest cavity. The babies have just 36 hours to reach the river or they will starve.

The drop from the nest to the forest floor might as well be a cliff. The ducklings weigh less than an ounce, and their wings cannot possibly carry them. But they try anyway, tumbling out of the cavity in a desperate scramble. Some hit leaves and bounce. Others land harder. Each one has its own style, its own survival instinct kicking in.

Mom hits the ground and issues a special call, a twittering sound she uses only this time each year. She needs to get them to the water where she can protect them. But the river sits a hundred feet away, and that distance might as well be a marathon.

The ducklings move in a tight cluster behind her, running when they can, hiding when they must. Foxes patrol these woods. Bobcats prowl the underbrush. Raptors circle overhead. And somewhere in the grass, a black rat snake waits at their level.

Some ducklings fall behind. A few miss the cue and find themselves alone in the forest, running a gauntlet where anything could be waiting. They stick together, two siblings racing toward water as fast as their tiny legs can carry them. They do not know it yet, but everything about their lives depends on what happens in the next few minutes.

The water appears like a lifeline. One by one, they splash in and swim to join the family. Mom leads them into the shallows where they can eat greens and bugs and grow strong.

The Oldest Hunters

Below the surface, something else moves. Alligator snapping turtles patrol the depths and shallows, appearing as rocks until they suddenly are not. Their metabolism is slow, their patience legendary, their jaws capable of crushing bones. These reptiles grow to more than 200 pounds and live for up to 70 years.

When the time comes, a female drags herself from the river and walks about 50 yards into the forest. She needs soft soil, somewhere she can dig without hitting bedrock. Using her hind legs like shovels, she excavates a nest that can take hours to complete. The digging continues well into the night, and every minute she spends on land is a minute she is vulnerable to predators.

When the cavity is ready, she enters what looks like a trance. Then, finally, she lays her eggs. Ten, perhaps fifty. She mated two months ago, and this may be the only contact she ever has with her offspring. She covers the nest carefully, then returns to the water, exhausted.

Three months later, the hatchlings break free from their rubbery shells. Unlike bird eggs, these do not crack cleanly. The baby turtles peck and claw their way out, dragging themselves from the nest cavity into a world full of predators. Blue herons stand three feet tall. Sunfish the size of dinner plates patrol the shallows. Everything seems bigger than this one-ounce creature fighting to reach the water.

But once they make it, their chances improve dramatically. They can camouflage themselves against the river bottom. They can use their snouts like snorkels and wait, motionless, for hours. They have become, essentially, living rocks. And if they survive the first year, they might live to see their 70th birthday.

Fish That Fly

Summer brings a different kind of chaos. Anglers navigate the low, six-foot-deep channels looking for white bass, unaware of what lurks just beneath the surface. When a boat engine fires up, something else does too. Asian carp launch themselves from the water en masse, a reflex triggered by anything that sounds or feels like danger.

These fish can weigh up to a hundred pounds, though the ones doing the most jumping are closer to five or ten pounds. They are not popular for eating in America, but they are impossible to ignore. They were introduced in the 1970s to control weeds on fish farms. Some escaped. They multiplied. Now they spread up the rivers and beyond, expected to reach 31 states and 40 percent of the continental United States.

The sound of a boat engine keeps them coming, which means every fisherman becomes an unwitting conductor of an aerial ballet. The carp launch themselves at the hulls of passing boats, sometimes breaking bones.

One Day to Live

Not everything that rises from the water brings danger. On certain summer evenings, a cool day triggers a phenomenon that has played out on the Middle Mississippi for millennia. Mayflies that have lived as nymphs in the river for more than a year suddenly hatch with wings and surface all at once.

They cling to the branches of trees like gray leaves in summer. Then they freeze, seemingly dead, while inside their old skin a new creature develops. This molting is their final transformation into adulthood, and it leaves them vulnerable. Blackbirds and grackles descend to feed. The buffet lasts just a few days each year.

Those that survive the birds emerge with new bodies and a single purpose: find a mate before the sun rises on another day. Most mayflies live just 24 hours after their transformation. They have no time to waste. They mate on the fly, creating clouds so dense they show up on Doppler radar. The females descend to lay their eggs in the river, sometimes as many as 10,000 each, before returning to the water from which they came.

When Winter Comes

The Ohio River doubles the discharge rate of.