Creatures that Return Each Summer to the Door Peninsula

By Coggin Heeringa, Interpretive Naturalist, Crossroads at Big Creek, Inc.

Our Door County summer residents, many of whom have, over the years, become Crossroads donors and volunteers, have returned. Some have raised their children here and now are sharing Crossroads and other natural areas with children and grandchildren.

Curiously, this week, each of our nature programs will focus on creatures that return each summer  to the Door Peninsula. Some bats, birds, butterflies and fish spend their entire lives here, but many species visit or live here seasonally.

So where do they go when they aren’t here? And do they, like our summer people, return each year to the same place?

Researchers are very interested in these questions, and because Crossroads Cove Estuary Preserve is a significant migratory stopover site, and because Big Creek is the spawning stream for northern pike and suckers, Crossroads participates in many research projects. 

Our Bat Hike on Friday night is a continuation of a bat monitoring project at three sites at Crossroads, begun two years ago by Dr. Gary Casper, and continued as part of citizen science monitoring in partnership with the WDNR. Using acoustic surveys, Crossroads has determined that hoary bats, big brown bats, Eastern red bats, and little brown bats are present, and others suspected. The Friday night hike will verify whether these species and others are still using Crossroads, and perhaps reveal their presence in sites that so far have not been monitored.

 Dr. Karen Murchie, Director of Freshwater Research at Shedd Aquarium in Chicago, studies sucker migration, and Big Creek is one of her many study sites in Door County. She, with the help of local citizen scientists, is collecting data to determine whether suckers return to the same creek each year and also hopes to learn where they go the rest of the year. 

For years, Crossroads staff and volunteers have inventoried migratory birds as a part of Cornell University’s eBird program, but this past year Crossroads installed a MOTUS tower at our Astronomy Campus. In doing so, we along with the Door County Land Trust and The Ridges Sanctuary, became a part of an international collaborative research network that uses coordinated, automated radio telemetry to facilitate research and education on the ecology and conservation of migratory birds.

“Motus works by having radio transmitters on birds and when they go near the towers, the radio signal is intercepted by that receiver,” said Jennifer Phillips-Vanderberg, the Lake Michigan Bird Observatory’s executive director. “It allows scientists to understand migration across the hemisphere on a different level than we have been able to in the past.”

Finally, as is our custom, Crossroads will collaborate with Wild Ones-Door Peninsula and the Door County Master Gardeners Association to offer a free  Monarch Butterfly tagging program in early  fall. A monarch butterfly does not return to the same place it was born. The monarchs we see flying this time of year are the grandchildren or even great-grandchildren of the monarch generation we tagged last year. Our data is sent to  Monarch Watch, an education, conservation, and research program based at the University of Kansas.

Bats, butterflies, birds and fish all visit Crossroads during their breeding season. We hope our summer people and our Door County residents, along with their kids and grandkids visit our three preserves, which are open all day, every day, free of charge.