By Sal Hertz, Seasonal Park Ranger, Mississippi National River and Recreation Area

The Visitor Center at the Upper St. Anthony Falls Lock and Dam sits at the heart of the Minneapolis’ mill district—one of the most intensively built areas of the river. Wildlife watching may not be top of mind, but the river is an engine for life of all kinds. Just steps from skyscrapers, you can walk out onto the lock and catch a glimpse of many flighted, finned and web-footed river residents. Grab your binoculars and keep a look out for these wildlife:

Osprey

Which raptor dive-bombs prey at speeds up to 80 miles per hour—plunging into the water, talons-first, to retrieve them? Osprey! These birds specialize in fish, and have found a great place to catch them at St. Anthony falls. Locks, dams and waterfalls create a barrier to passage for fish, and so they tend to congregate there—increasing the odds of success for a hungry Osprey. One osprey was recently seen diving in just above the horseshoe dam.

Osprey adapt well to human landscapes and will build nests on human structures like electric lines and channel markers. This summer, multiple osprey sightings at St. Anthony Falls suggests that there might be a nest nearby with recently-fledged juveniles.

Doubled-created cormorants perched on a branch near the St. Anthony Falls Lock and Dam. Photo by Sal Hertz / National Park Service. 2021.

Double-crested Cormorants

Look no further than the limestone rocks above St. Anthony Falls to spot these long-necked, jet black birds. Double-crested cormorants have less preen oil than other birds, which means they lack waterproofing—you might notice them with wings outstretched to air dry. This seeming disadvantage may actually make them more agile divers and hunters. Look closely and you may spot a cormorant surfacing from a dive above the lock with a small fish in their hooked bill.

Cormorants are known to repurpose trash from the human landscape around them into their nests. The closest nesting colony of cormorants is just a few miles upstream on two islands by Marshall Terrace Park. There, they build nests in tree branches alongside other long-beaked fishing birds—great blue herons and great egrets.

While Ranger Bri was giving a tour at Upper St. Anthony Falls Lock Visitor Center this summer, someone noticed a turtle take a tumble on the concrete stairs near the falls. After assessing the scene, the large spiny softshell turtle was carefully es… — While Ranger Bri was giving a tour at Upper St. Anthony Falls Lock Visitor Center this summer, someone noticed a turtle take a tumble on the concrete stairs near the falls. After assessing the scene, the large spiny softshell turtle was carefully escorted out of the “authorized personnel only” area and gently placed back towards the Mississippi River. Photo by Sal Hertz / National Park Service. 2021.

Softshell Turtles

St. Anthony Falls is not just for the birds—one look down the lock wall might reveal a softshell turtle, paddling along the wall, or sunning on a log swept in by the current. These turtles are equipped for life in the water, with fully webbed feet and the ability to breathe through their skin to get up to half of their oxygen underwater (the rest is breathed through their lungs at the surface). This superpower helps them as ambush predators—they hide in mud on the bottom of the river with only their head sticking out to snatch unsuspecting fish, insects and crayfish.

Recently, an enormous Spiny Softshell has been spotted around St. Anthony Falls. The soft, rubbery shell of female Spiny Softshells can grow over a foot and a half long in their 50 year life span (males can reach about half that size). This is as big as any turtle gets in Minnesota! What about the “spines” of the “spiny softshell”? This part of the name refers to the small bumps at the front of the shell, just behind the turtle's head. Another species you might see is the smooth softshell, who lacks the shell bumps but has a more defined eye stripe.

Wood Ducks

Turtles aren’t the only ones paddling into the lock—this summer, a female Wood Duck and a duckling resided there—swimming and resting on driftwood. Mingled in with all of the trash that collects in the back current of the lock is a feast of duckweed and bugs.

Wood Ducks are cavity nesters who lay around a dozen eggs in tree hollows near water. The most successful nests are often near backwater lakes and streams with plenty of places to hide from predators like raccoons and northern pike. The lack of nooks and crannies for ducklings to hide in on the urban riverfront might explain why there was only one duckling in the lock.

Common carp

See a plump, scaly fish in the water? It’s likely a Common carp. Their large, vacuum-cleaner-mouths rise to the surface during mass-hatches of insects like mayflies. Between hatches, they pursue dinner high and low—opportunistically feeding on water plants, insects, bottom-dwelling worms, and crustaceans—including zooplankton.

Common carp were introduced across much of the United States as a game fish in the 1880s. As they rapidly reproduced and spread through connected waterways, it became apparent that Common carp are bad for water quality. Carp are messy foragers—while they are nosing around the river bottom looking for insect larvae, they uproot whole plants and stir up sediment, which causes cloudy water and algae blooms.

It is important to note, however, that Common carp are not one of the species of Asian carp (Bighead, Silver, Grass and Black) that contributed to the closure of the Upper St. Anthony Falls Lock and Dam. These Asian carp species have not yet been found near St. Anthony Falls. When they are, the barriers of the waterfall and closed lock will hopefully block them and prevent further ecological havoc upstream.

A cedar waxwing sits on a branch near the St. Anthony Falls Lock and Dam. Photo by Sal Hertz / National Park Service. 2021.

Flying Insect-eaters

In natural areas, the Northern Rough-winged Swallow nests in burrows in banks near water. However, this summer, a nesting pair took advantage of circular openings in the lock wall to raise their young. These aerial acrobats catch tiny flying insects midair, or pluck them from the surface of water. Dislike mosquitoes? Swallows are on your team.

The cries of not-yet-fledged Cedar Waxwings were recently overheard near the entrance to the lock. These mostly-fruit-eaters built their nest near the river to supplement their diet with protein-rich insects like dragonflies, stoneflies and mayflies, which emerge from the river in abundance.

Chimney Swifts—also known as “flying cigars”—spend their days in constant flight, feeding on everything from wasps to craneflies. They lack the ability to perch; at night, Chimney Swifts roost by clinging to vertical walls inside hollow trees, caves, and in the city—old brick chimneys.

What other wildlife will you discover at Upper St. Anthony Falls Lock and Dam? Find information to plan your visit on the park’s website.

Wildlife on the Minneapolis Riverfront