What’s in this Season?

Autumn is a season of change in South Dakota. Migrating birds flee to warmer climates. Hoofed mammals shift into their breeding season, activating the “rut.” And South Dakota’s tree canopy turns from its summertime green to a kaleidoscope of yellow, red, orange and brown. Don’t hesitate to get outside and enjoy nature’s signs of change—this season won’t last long.  

Fall Color

The spectacular fall colors arrive in South Dakota in late September and continue throughout October.

Many of those colors have been present in leaves during the entire growing season but masked by chlorophyll, the light-absorbing green pigment that is essential for photosynthesis. When the days shorten in the fall, photosynthesis slows and eventually ceases, causing deciduous trees to stop making chlorophyll and allowing other pigments in leaves to become visible. Carotenoids are the pigments responsible for yellows, oranges and browns; anthocyanins create reds and purples; and mixes of the two pigments result in bronzes and deeper shades of orange.  

Location, weather and type of tree determine when this color change takes place. Cooler locations are where the transition begins, causing trees at higher elevations to change color first. However, timing can change from year to year, influenced by temperature and rainfall. Drought causes less brilliant colors and trees in dry years drop their leaves earlier. At any one location, tree species also determine fall color. Ashes are known for their early color change. Aspens, cottonwoods and maples often follow, and oaks change color later. Evergreens, of course, don’t change color or drop their needles, causing the dark greens of the Black Hills’ pines to contrast vividly with deciduous trees in October.

The Rut

Fall is the season of courtship for many mammals in South Dakota. Their offspring do best if born soon after winter has ended, when they have time to grow before the return of harsh weather. This fall breeding season for hoofed mammals is called the rut. This is the time of year when antlers and horns become essential—males use their headgear to compete for females and spectacular clashes can occur. 

Waterfowl Migration

 South Dakota’s Prairie Coteau region is known as the “duck factory of the world.” The region is dotted with small prairie ponds called potholes that were formed when glaciers covered this landscape.

Ducks and geese are excellent subjects for beginning birders since they often are easily seen on open water, unlike small songbirds that can be hidden behind leaves. Most have distinctive field marks and behaviors that can be quickly recognized with practice.

Grab a field guide and binoculars and look for waterfowl at wetlands such as Sand Lake National Wildlife Refuge. The Wildlife Drive Auto Route closes for the season at dusk on October 14, but the Migration Observation Area remains open and is a good spot for watching the thousands of snow geese that visit the refuge in the fall. Sandhill cranes are another impressive bird that migrates through the state in the fall. Listen for their bugling calls then look for their flocks often flying past high overhead.

Winter in South Dakota is cold and snowy, but that should not keep you from exploring the outdoors! The trails are quiet and chances are, you may be the only one braving the elements. Embrace the solitude and soak in the mental health benefits the snowy plains and icy ponds have to offer. Bundle up and grab your snowshoes. There is so much going on in nature even on the chilliest days.

Birds

Winter is the best time for birding because there are no leaves on the trees. It makes spotting birds much easier. Although many birds flee South Dakota during the cold winter months, we have some year-round resident birds that you can surely spot around the state, like American Goldfinch, woodpeckers and blue jays. You could even see a Northern shrike, which visits the Dakotas in the winter, returning to northern Canada to nest in the summer. These birds are fierce hunters. Shrikes attack and kill a variety of prey: other birds, mice, lizards, insects; at times even tackling prey larger than themselves (a shrike is about the size of a robin). They kill using their hooked beak; their feet are too weak to kill with grasping talons like hawks and owls. A shrike might not eat its prey immediately. Instead, the bird carries its prey to a larder where it will store food items impaled on barbed wire, thorns, broken twigs, or simply wedged into the fork of two branches. Sighting a shrike could be difficult. In the winter, you might first find evidence of shrike predation—dead sparrows or mice skewered on thorns or barbed wire—before spotting a shrike hunting nearby.

Occasionally, South Dakota sees snowy owls, visiting all the way from Alaska, Arctic Canada and Greenland. Their plumage reflects their northern home: the birds are white as snow, although females and young birds are barred with black. Their face is always bright white and highlights their brilliant yellow eyes.

Bison

Much of South Dakota’s wildlife either migrates or hibernates to escape the harsh winter. But bison seem to thrive in the cold. They’re animals built for life on the prairie year-round. Visitors to parks and preserves with bison herds enjoy watching bulls, cows and calves mingling together during the summer months. Come late fall, the bulls wander off to form “bachelor bands” and the cows, calves and non-breeding bulls stay together in small herds. These dispersed, separate groups make for fewer animals looking for food in the same place once winter snows make forage hard to find. It’s a good survival strategy.  

Bison eat less in the winter. Their metabolism actually slows, allowing them to survive on less forage. Using powerful neck muscles, bison swing their massive heads to push snow out of their way to reach forage beneath. Bison also are good at staying warm. Their summer coat turns dark brown in the fall and develops a dense undercoat of woolly hair that provides insulation during cold weather. Guard hairs provide added protection and are longest on the front half of a bison’s body, covering the head, neck, forelimbs and tall hump above the shoulders. The winter coat on a bull bison can be as much as six inches thick over the hump. During a storm, bison turn and face into the wind, causing these long hairs to lie down against the body, maximizing their insulating ability. Their winter coat insulates so well that a storm’s snow simply accumulates on the animals, unable to be melted by their body heat.

Places to Visit

There is no shortage of places to experience the natural world in a South Dakota winter, but here are some of our recommendations.

• Black Hills: The 1.2-million-acre Black Hills National Forest gets more than 150 inches of snow every year. Enjoy the winter wonderland on skis at Terry Peak Ski Area near Deadwood, or ice climbing in Spearfish, or on snowshoes in one of the state parks.

• Samuel H. Ordway, Jr. Memorial Prairie: Stop by this Nature Conservancy preserve in Leola to try to catch a glimpse of bison enduring the winter.

• Lake Oahe: Try your hand at ice fishing on Lake Oahe near Pierre. It’s a great way to get outdoors in the chilliest months. 

The signs of spring are always welcome after a long South Dakota winter. From early spring flowers popping up through the snow-crusted prairie to critters frantically seeking a mate, spring is a time for beauty and renewal. Enjoy the trickling waters of a slowly thawing river or lace up your boots for a tromp along a muddy trail. Take time to observe the hints of spring all around you.

Cuteness alert

Spring has sprung when cinnamon-colored baby bison appear on the prairie. 

Most bison calves are born in May and June. Pregnant cows first chase off their offspring from the previous spring: yearlings that stay with the herd but can no longer rely on their mother’s care once a newborn arrives. Shortly before giving birth, a cow will move to the edge of the herd or leave the group altogether. The process takes only about 20 minutes and the calf can stand on its own after another half hour and run with the herd within one to three hours. 

After their first few weeks, young bison become more adventurous and may wander away from their mothers to explore the herd. They often form nursery groups: two to three dozen calves that are tended by a few cows. This is a good time to watch the young animals – bison watchers can see them learn from their mothers, begin to graze and sort out who is dominant in their groups.  

Early blooms

The pasque flower is one of the first flowers to bloom on South Dakota’s grasslands. You may even see it blooming out of the melting snow. Pasque flowers thrive on prairies with sandy soils, like TNC’s Sioux Prairie. Nature writer Aldo Leopold wrote in A Sand County Almanac, “The chance to find a pasque flower is a right as inalienable as free speech.” Find a pasque flower and know unquestionably that spring has arrived on the prairie.  

Spectacular courtship

The courting displays of sharp-tailed grouse are fascinating to watch in the spring. These chicken-like birds gather at a lek, a patch of ground where males compete for the attention of hens by performing a dance display at dawn. Dancing grouse spread their wings, lower their heads and raise the short, bright yellow feathers above their eyes.   

The tail is raised and spread like a fan and the birds rush forward or turn in tight circles, rapidly stamping their feet and rattling their tail feathers. The males inflate and deflate prominent purple neck sacs, cooing and cackling. They also fight—within the lek, each bird has a small territory. These territories are hotly contested, as hens may prefer males in some locations over others. 

Prairie dogs get busy

In the early spring, prairie dogs become more active. Longer days trigger the start of their mating season after a winter spent mostly in their warm burrows. When mating begins, prairie dogs become aggressive and territorial, chasing off other dogs that intrude onto their coterie, or family unit of one breeding male, a few females and offspring. 

Fights between competing males are not uncommon. The dominant male dog seeks to prevent others from mating with the females in his coterie. Males call to females by making a “chirk” call similar to—but slower—than the predator warning call familiar to prairie dog watchers. Males also help females build their underground nests and dog watchers can see paired animals gathering nesting material and carrying it into their burrows. Mating takes place underground and is rarely seen.   

Summer: it’s what makes the South Dakota winter worth it. 

Throughout the season, the state is abloom with wildflowers. Every few weeks a new suite of plants is opening delicate petals to the bees and butterflies seeking out nectar.

If you get out on a hike, whether short and sweet or long and challenging, you’ll see plenty of birds and other wildlife across the state. Everyone is out enjoying the warm weather!

Here’s what else you can discover in nature this summer in South Dakota.