Wisconsin Nature Through the Seasons

Colorful Foliage

Cooler temperatures and shorter days mean the trees begin to change into their autumn splendor. The change in seasons signals to the trees to stop their food making processes, and the green chlorophyll of the leaves begins to break down, allowing the reds, oranges and yellows of the leaves to shine. Without a doubt, the Baraboo Hills have some of the most brilliant and beautiful fall foliage and are a must-see in the autumn. Pro-tip: If you want the most up-to-date information on the peak of fall foliage around Wisconsin, visit Travel Wisconsin’s Fall Color Report. 

Mammals on the Move

Fall is a great time to spot mammals in the wild, as they are preparing for the upcoming cold season. Beginning in August (to avoid disturbing ground-nesting birds), trails are mowed and maintained at Lulu Lake Preserve and the Newell and Ann Meyer Nature Preserve, and you may be able to see red fox, beaver, muskrats or even badgers. Early fall is the mating season for white-tailed deer and is an excellent time to spot heavily antlered large bucks. In northwest Wisconsin and Jackson County, be sure to keep your ears open for the bugling call of male elk as they seek mates in their breeding season.

Pro-tip: Hunting is permitted on many TNC preserves, so if you are hiking in the fall, please wear blaze orange as a safety precaution.

Golden Prairies 

In late August through October, Thomson Memorial Prairie and Barneveld Prairie become blanketed in asters from white to bright purple and the brilliant yellow of goldenrods. These plants are a vital source of nectar for many pollinators, but none so much as the iconic monarch butterfly. These beautiful orange and black butterflies are gearing up for one of the most extraordinary migrations of the animal kingdom, as they prepare to fly south to Mexico to overwinter.

Fun fact: While goldenrod often gets the blame for fall allergies, its pollen is too heavy to be carried by the wind. It relies solely on pollinators like the monarch to spread its pollen. Instead, the less conspicuous, but just as common, ragweed, is the culprit causing much of the fall allergies we experience. 

Pro-Tip: Thanks to the lake-effect, the Door Peninsula has some of the softest, fluffiest snow for cross-country skiing and snowshoeing!

Whooo Goes There?

Winter is prime owl season in Wisconsin. Not only are these magnificent birds easier to spot with the leaves off the trees, but many species, like great horned owls, begin their nesting and breeding season in late winter. The true owl stars of winter, though, are the snowy owls that visit northern Wisconsin and the Door Peninsula. Snowy owls are generally an Arctic species, however, small numbers reach Wisconsin each year. Every handful of years, large numbers move into the state, an event known as an "irruption." What causes these irruptions is not entirely understood, but they provide a wonderful opportunity for more people in Wisconsin to spot these beautiful owls.

Bald Eagles

Beginning in January and February, bald eagles begin to reclaim and rebuild their nesting sites across the state. Typically, eagles begin nesting earlier in the south and later in the season the farther north you go. They nest and breed early in the year to have plenty of time to incubate eggs and raise their young before winter begins to roll back in. Thanks to intensive conservation efforts since the 1970s, the bald eagle population has rebounded across North America and in Wisconsin especially. These magnificent birds have documented active nests in all but one county in Wisconsin, and you have a good chance of spotting them in winter along any waterway. They’ve been spotted at Lulu Lake Preserve in the Mukwonago River Watershed, all preserves on the Door Peninsula and at our Northwoods preserves.

Blooms and Blossoms

For those weary of winter, TNC preserves in the Baraboo Hills and the Door Peninsula offer an abundance of early signs of spring: ephemeral wildflowers unfurling their blooms in the still chilly air. These perennial wildflowers—such as spring beauty, bloodroot, trout lilies and large-flowered trillium—bloom for a brief time at the beginning of spring. They’re often small and nestled into forest floors and marshes, so we recommend a slow and careful pace on the trails to look for wildflowers! 

Songbird Spring Migration

Wisconsin is a birder’s paradise, especially in spring! Between March and June, nearly 300 species of birds from South and Central America, the Caribbean and the southern U.S. stop to rest or nest in Wisconsin.

As many as 250 different bird species either breed in the Baraboo Hills or pass through during migration. TNC preserves in the Door Peninsula offer some of the best birding in the state since many species of migrating birds follow insect hatches along the Lake Michigan shoreline. Northern Wisconsin hosts 24 breeding species of warblers in places like the Catherine Wolter Wilderness Area. These far northern specialists include species like palm, Blackburnian, black-throated blue, Northern parula and magnolia warblers.

Pro tip: If you go hiking at any of our preserves in the summer, wear sunscreen and use insect repellent to ward off ticks, mosquitos, flies and other biting pests. 

Peak Prairie Season

From late May through August, there is nothing quite like the wild and vivid colors of wildflowers like blazing star, wild bergamot and common spiderwort blooming in the diverse prairies of the Military Ridge Prairie Heritage Area. Keep an eye out for the tall compass plants, which are well adapted to hot and dry conditions thanks to their ability to orient their leaves north to south to avoid direct noonday sun. But the standout is the prickly pear cactus blooming at Spring Green Preserve in June and July. In this protected place, the prickly pear cacti grow in dense patches, each large, waxy yellow flower blooming for a single day, then disappearing.

Nighthawks on the Move

In August, nighthawks begin to leave Wisconsin, with the peak of their migration—sometimes thousands in one evening—happening late in the month. Nighthawks leave TNC preserves in Northern Wisconsin early because they require a constant supply of flying insects, which begin to disappear as the weather cools. In their migration, nighthawks will fly thousands of miles to southern South America, one of the longest migration routes traveled by any North American bird. Look for nighthawks close to evening, flyingover open fields, near airports and along highways.