Well, they’re off! When the wind sails in from the north, it’s a signal to all kinds of creatures: “Time to go!” So they take wing singly and in large flocks, letting the flow of cool air support them, carrying them quickly onward as they beat wings of all sizes to make their way to warmer climes.
And of course, it’s not just birds. Above you can see our friend Nancy Isken’s photo of Monarch Butterflies (Danaus plexippus) last week resting at Tawas Point State Park before crossing Saginaw Bay. They were beginning their long journey to Mexico where they will spend the winter. In the spring, these Monarchs will make the first leg of the journey back north, stopping in warm areas like Texas to produce a new crop of butterflies who continue heading north. These new generations will fly only a few hundred miles, stop and reproduce, completing their whole life cycle in only 5-7 weeks. So it takes several generations to complete the trip back to Michigan each summer. Sarina Jepson of the Xerces Society, which is focused on invertebrate conservation, says in a fine National Geographic article, “…when fall rolls around again, a special ‘super generation’ of monarchs that can live up to eight months will make use of air currents to wing all the way back to Mexico—a seemingly impossible feat for such a delicate-looking insect.” Imagine that! So the Monarch butterflies born here In Oakland Township each summer can potentially live for 8 months instead of 5-7 weeks and fly 3,000 miles instead of a few hundred. We are living among real, live superheroes!
And Monarchs aren’t the only insects that migrate. Green Darner Dragonflies (Anax junius) (also tracked by the Xerces Society) travel down to Texas and Mexico as well. For dragonflies, it also takes many generations of reproduction before their trip is completed, though their migration is less well understood. But again, like the Monarch generations that arrive here each summer, the dragonfly offspring seem to know how to find their way in the right direction. Citizen science and research is helping explore dragonfly migration. But for now, I love a good nature mystery, don’t you?
Painted Lady butterflies (Vanessa cardui) make multiple generation migrations all over the world. But they migrate erratically. Some years they migrate and some years they don’t. And the direction and route can vary widely. Some experts speculate that their migration routes may be affected by dramatic changes in weather and climate – another nature mystery yet to be solved.
At this time of year, the night sky begins to fill with thousands, even millions, of birds riding the wind south in the darkness, navigating by the stars or the setting sun, or by sensing the earth’s magnetic field. Some may navigate by landmarks or simply remembering good feeding grounds. And amazingly, most juvenile migrating birds, like those insects hatching during migration, somehow know how to find their way without any help from adults! Cornell’s BirdCast website is a great way to watch the flow of birds across the United States day by day throughout the fall.
Remember all those bright little warblers, unusual sparrows and other small birds that sailed up here on a south wind in May? Well, most of them have now finished breeding farther north and are beginning to make their way back to more warmth and sunshine. They’ve molted out of their bright breeding feathers so they’re a little less colorful now and their routes vary a bit depending on available food and weather. But keep a look out for these little travelers starting now. Here are a few from the autumn of previous years:
If you’re thinking you’d like to see some bird migrations in BIG numbers, you might check out the Hawk Fest featuring hawks, eagles, falcons and owls at Lake Erie Metropark on September 15 and 16. Or if you love our Sandhill Cranes (Grus canadensis), consider a trip to the Audubon Society’s Cranefest at Big Marsh Lake in Bellevue, Michigan (near Battle Creek) on October 13 and 14.
Of course, if you want to stay close to home, you’ll be warmly welcomed at our Oakland Township Wednesday morning bird walks. The walks rotate through our township parks each month and in September and October, they start at 8 a.m. The schedule is available year ’round if you click on the drop-down menu above for “Stewardship Events.” We’re a friendly group with some experienced birders who are glad to help beginners see their first migrators. Bring your binoculars or borrow a set from Ben, our Natural Areas Stewardship Manager, who leads the walks.
So yes, summer is waning. But I can’t help feeling celebratory as autumn air turns crisp and the skies fill with winged creatures. I recommend looking upward this fall and perhaps wishing “Bon Voyage!”, to our migrators who provide such beauty and mystery as they find their paths through the air.