Things are changing—some quickly and some with glacial slowness—at Crossroads at Big Creek, and this week our programs will reflect on some of those changes. So what is glacial slowness? Geologists estimate that during the last Ice Age, the glacier moved over the Door Peninsula at one to four inches per day, when it wasn’t stalled, which it sometimes was.
The topic of the family program Journeys with Joan at 1:00 on Monday, July 28, is butterflies, and for them, change happens quickly. Participants will likely see monarch butterflies flitting among common milkweed blossoms, sipping nectar, though monarchs tend to prefer other flowers for feeding.
Females are more likely to search for tender milkweed leaves on which to lay their eggs. Joan will explain that a monarch develops from a tiny egg about the size of a grain of sand to an adult butterfly in 29-32 days, depending on temperature. Other butterfly species may develop even faster, but in the grand scheme of things, it's an impressively rapid transformation.
The next day, the Journey with Joan program will focus on glaciers—the iconic example of slow change. But the formation of the Great Lakes has also been slow. The retreat of the last glacier began more than 10,000 years ago, and the landscape is still recovering.
The ice sheets were so massive that they depressed the Earth’s crust. When the ice melted, the land began to rebound, while the volume of water in what is now Lake Michigan fluctuated wildly for millennia. Today, the land around Sturgeon Bay is still rising a few millimeters per year, while nearby areas are sinking ever so slightly.
On Wednesday, the Journey with Joan program will discuss caves, another testament to slow geologic change. Approximately two million years ago, glaciers scoured away the overlying soil and rock, exposing the region’s Silurian dolomite bedrock. Since then, slightly acidic rainwater—formed when rain mixes with carbon dioxide in the atmosphere and soil—has slowly widened fractures in the dolomite, creating the caves and sinkholes we see today.
Finally, our Nature Trek with Terrie will transform participants into "Nature Detectives." Learners of all ages will explore Crossroads’ diverse terrestrial and aquatic habitats, searching for clues about who lives there, what they eat, and where they go.
Looking ahead, on Saturday, September 6, the community is invited to further explore our habitats during the Second Annual Trails & Ales event. We encourage early registration—discounted pricing is available through the end of July. Proceeds support programming and outreach at Crossroads at Big Creek. For details and tickets, visit the Crossroads website.
Monday, July 28
1:00:Journeys with Joan- Butterflies
Butterflies are masters of change, and participants will search for these remarkable insects in the gardens, meadows, and fields of Crossroads. This free, family-friendly nature program is open to all ages and requires no registration. Meet at the Collins Learning Center, Crossroads, 2041 Michigan Street, Sturgeon Bay.
Tuesday, July 29
1:00 p.m., Journeys with Joan: Glaciers to Great Lakes
Learners of all ages will explore how massive glacial ice shaped the landscapes we know today. Discover how these ancient forces helped form Wisconsin’s most precious resource—our Great Lakes. Free and open to the public. Meet at the Collins Learning Center, Crossroads, 2041 Michigan Street, Sturgeon Bay.
Wednesday, July 30
1:00 p.m. Journeys with Joan: Rocks & Caves of Door County
Learners of all ages will delve into the geological history of the region. Learn how Door County’s caves formed over millions of years in the layers of ancient dolomite bedrock. Free and open to the public. Meet at the Collins Learning Center, Crossroads, 2041 Michigan, Sturgeon Bay
1:30 p.m. Wandering Wednesday
This gentle, one-hour walk led by a naturalist is perfect for all ages. Meet at the Collins Learning Center, Crossroads, 2041 Michigan Street, Sturgeon Bay.
Thursday, July 31
1:00 p.m., Nature Treks with Terrie
Participants of all ages are to take a deep dive into local ecology. Join naturalist Terrie Cooper on a discovery hike to explore Crossroads’ forests, fields, and wetlands while searching for clues about who lives there, what they eat, and how they travel through the landscape. Reservations required. See www.crossroadsatbigcreek.org Events for more information and to register.
