By Tom Pink
As much as I enjoy summer, I look forward to September, when I’m in a waterfowl blind, watching the seasons change. The prospect of a duck or goose dinner is fine, but the allure of waterfowling is watching “the old and unsolved mystery of migration,” as Gordon MacQuarrie once wrote.
In recent years, I’ve noticed birds weren’t the only things flying over my decoys in the fall, especially early in the season. Monarch butterflies were gliding across the river from Canada. Could they be migrating, also?
to warmer climates, ensuring the survival of the species.
As it turns out, yes they are. Every year, monarchs, one of our most recognized butterflies, make their way from their northern range to spend winter in the south, largely in the Sierra Madre Mountains of Mexico. A western population winters in California. It’s on the wintering grounds, where they’re concentrated, that it’s easier to gauge their population status, which has been showing a decline in recent years.
According to the U.S. Forest Service, monarchs are the only butterfly known to make a north-south migration similar to birds. They use air currents to cover 50-100 miles a day. The fall migration is a straight shot, but the way north is progressive, with the overwintering monarchs producing young that continue the journey north.
Monarchs spend the winter in forests with an elevation nearly two miles above sea level -- much higher than their U.P. summer homes -- because of the microclimate those regions provide. The humidity allows them to conserve energy and preserve fat reserves. I know from cleaning ducks and geese that waterfowl add fat to sustain them in migration -- but butterflies?
Birds, which migrate mostly at night, use magneto-receptive cells in their brains and magnetically sensitive proteins in their eyes to find their way south. Migrating monarchs are thought to use the magnetic pull of the earth to help them navigate, too.
Monarchs rely on milkweed for egg-laying and caterpillar sustenance. While common milkweed is still fairly plentiful here in the north, it and other milkweed varieties are in decline elsewhere due to pesticide use and mowing, according to the Monarch Joint Venture. No doubt you’ve seen milkweed pods in the fall dispersing fluffy seeds like dandelions scattering theirs in spring. A closer inspection in late summer might reveal monarch caterpillars getting lunch or a butterfly emerging from a chrysalis.
What can you do to help migrating monarchs in your neck of the woods? Encourage milkweed and wildflower growth and limit pesticide use. Michigan State University Extension offers advice on how to do it.
You can also support environmental groups, such as the Mackinac Straits Raptor Watch based out of St. Ignace, which has tagged migrating monarchs to help monitor their status. The group includes a tally of monarchs in spring and fall raptor counts.
When the ducks aren’t flying over your decoys this fall, keep an eye out for migrating monarchs, but don’t shoot them, no matter how fat they may be. The southern edge of the Cloverland coverage area from DeTour to the Garden Peninsula is a good region to see monarchs as they gather to cross the lake.
Tom Pink of Sault Ste. Marie has been a freelance writer for 40 years. He loves to hunt, fish, hike, forage and paddle his stand-up paddleboard throughout the state, but his favorite place is the Eastern Upper Peninsula.
Photos courtesy of Sharron Dorrity of Sault Ste. Marie