A thousand-mile journey on two-inch wings

Post by Jen Berlinghof

I’ve spent many days this summer living the “lake life,” from the sandy dunes of the Great Lakes to the cattail-studded coves of inland waters. The waterways found within the Lake County Forest Preserves in northern Illinois have been especially rewarding. Each shoreline has provided unique glimpses of wildlife, including an osprey (Pandion haliaetus) diving full throttle to catch a fish at dawn, and a red fox (Vulpes vulpes) pouncing on prey hidden among the beach grass at dusk.

Also present at every waterway this summer has been the jewel-hued, common green darner dragonfly (Anax junius). These ubiquitous insects effortlessly nab multitudes of mosquitoes on the wing. While the monarch butterfly (Danaus plexippus) reigns in our minds when it comes to insect migrations, recent research reveals the green darner takes a multi-generational, miles-long journey of its own each year.

Common green darner dragonflies (Anax junius) are found in the forest preserves. Stock photo.
Common green darner dragonflies (Anax junius) are found in the forest preserves. Stock photo.

Wildlife migrations are typically monitored using small tracking devices called geolocators. Songbirds and monarchs migrate in such large flocks or swarms that their travels can actually be detected by radar. But green darner dragonflies don’t usually migrate in large groups. Coupled with the fact that the technology to fit an insect weighing as little as a paperclip with a teeny transmitter is only in its infancy, scientists have faced a conundrum of how to track the marvelous migrations of these members of the Odonata order.

A video explaining how researchers revealed green darner migration patterns.

A combo of chemistry and community science provided insight into the last century of dragonfly migrations, as well as environmental impacts for future generations of flyers. Research published in the December 2018 issue of the scientific journal Biology Letters was the first of its kind to use the chemical signatures of dragonfly wing samples to describe the nearly thousand-mile journey these insects undertake on two-inch wings.

A green darner dragonfly nymph. Dragonflies and damselflies of Lake County spend the majority of their lives in this underwater stage of development—anywhere from one to four years, depending on the species. Photo © John C. Abbott & Kendra K. Abbott, Abbott Nature Photography.
A green darner dragonfly nymph. Dragonflies and damselflies of Lake County spend the majority of their lives in this underwater stage of development—anywhere from one to four years, depending on the species. Photo © John C. Abbott & Kendra K. Abbott, Abbott Nature Photography.

A record of the birth waters of every dragonfly is stored chemically in the form of a hydrogen isotope. According to the Department of Energy, isotopes are “members of a family of an element that all have the same number of protons but different numbers of neutrons.” The specific isotopes found in water vary geographically.

As swimming nymphs, dragonflies absorb the isotopes into their bodies and eventually incorporate them into the substance that forms their adult wings. Researchers extracted these chemical trademarks from hundreds of wing samples, pinpointing the general area of North America each insect originated from.

With the home bases for different darners known, migration factors had to be determined. Researchers turned to decades of community science data that suggested these dynamo dragonflies were motivated to move based on temperature and the amount of daylight.

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Areas with many dragonflies are represented in red. Areas with no dragonflies at the given point in time are represented in gray. Graphic © Matthew Dodder via Hallworth et al., Biology Letters.

The researchers determined it takes three generations of green darner dragonflies to complete the migration cycle from southern North America to the north, then back again south.

In spring, a first-generation dragonfly nymph emerges from a pond in the American South, sheds its exoskeleton, unfurls its glossy wings and flies 400-500 miles north to lay its eggs before dying. These eggs hatch and complete their metamorphosis by late summer in northern waters.

Some of this second generation will stay put, overwintering as nymphs and waiting out the cold, hunkered down like the rest of us in the Upper Midwest and Northeast. Other members of the second generation have the “travel bug” and hightail it south to lay eggs by late fall along the Gulf and Atlantic Coasts.

This third and final batch of eggs hatches over winter and the adults remain in the warm waters of the South, soaking up the sun. The eggs laid by this third, non-migratory generation will kick off the migration cycle the following spring.

Green darners are named after their resemblance to a darning needle. Photo © Phil Hauck.
Green darners are named after their resemblance to a darning needle. Photo © Phil Hauck.

As summer comes to a close, I’m still striving to live the “lake life.” I walk along the Lake Michigan shoreline at Fort Sheridan in Lake Forest and watch soaring raptors ride thermals overhead as hawk migration gets underway. Closer to the ground, green darner dragonflies zip by on their shimmering wings. Thanks to chemistry and community science, I’m keenly aware of the dual migrations that stratify the skies.

To witness green darners and other wildlife migrating, you might try our Hike Lake County Challenge, now in its 23rd year. Complete seven of the 12 designated trail routes between now and November 30, and you’ll earn a free commemorative shield or zipper pull. Bring your dog along and Fluffy will receive a commemorative dog tag for their collar! See this year’s trails.

What’s wrong with this picture?

Editor’s note: hey readers, Brett Peto here. This month, guest author Pati Vitt, Manager of Restoration Ecology at the Lake County Forest Preserves in northern Illinois, returns with the third part of her series about our research project to restore 180 acres of former farmland within Grant Woods Forest Preserve in Ingleside using a climate-adapted, regionally sourced native seed mix.

This past winter, we planted 800 pounds of native grass seed from southern Illinois and Kentucky in the project area. The goal was (and still is) to help us understand whether we should source native seeds from further south to make our future restoration projects more resilient to climate change.

Unfortunately, as you can probably tell from the photo below, even the best-laid plans can go awry. And so they did, when an unseasonable early drought struck. Pati will pick it up from here.

The author's boot atop a drought-parched patch of soil at Grant Woods in Ingleside. Photo © Lake County Forest Preserves.
The author’s boot atop a drought-parched patch of soil at Grant Woods in Ingleside. Photo © Lake County Forest Preserves.
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Become a community scientist

Post by Jen Berlinghof

While the past year and a half has kept many of us mostly at home, nature in our backyards and beyond has provided a balm for these trying times. General use of the Lake County Forest Preserves in northern Illinois is trending 30% higher in 2021 than a typical pre-pandemic year. And in 2020, there was an astounding 70% surge in visitation. The number of folks delving into home gardening and backyard birding has skyrocketed as well, making headlines by leaving store shelves bare of birdseed and bird feeders. The COVID-19 pandemic has amplified our desire to connect to nature closer to home, and it has created space and time for local, daily observations. All of this translates to an environment ripe for community science, also called citizen science.

Community scientists flip over a cover board during a BioBlitz event held at Middlefork Savanna in Lake Forest in 2008. Photo © Carol Freeman.
Community scientists flip over a cover board during a BioBlitz event held at Middlefork Savanna in Lake Forest in 2008. Photo © Carol Freeman.
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A native garden to call your own

Guest post by Eileen Davis

What is your earliest gardening memory? Was it planting a seed in a paper cup at school, and watching it sprout and grow on the classroom windowsill? Perhaps you gathered dandelion flowers and presented your mom with a beautiful, yellow bouquet. Or did you rake up a giant pile of leaves to jump in on a crisp fall day? You might even have visited the native garden at Independence Grove in Libertyville, part of the Lake County Forest Preserves in northern Illinois.

My earliest gardening memory is helping my aunt and uncle in their garden. I was only about four or five years old, but I clearly remember the prickly feeling of the cucumber vines scratching my forearm as I helped pull weeds. No matter the memory, we are all doing the same thing—tending to our little piece of the Earth. It’s something humans have done for thousands and thousands of years. We are and always have been dependent on our environment for survival.

The author's daughters playing in a backyard leaf pile. Photo © Eileen Davis.
The author’s daughters playing in a backyard leaf pile. Photo © Eileen Davis.
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The cunning of cowbirds

Post by Jen Berlinghof

Bird migration is well underway, and the nesting season is upon us at the Lake County Forest Preserves in northern Illinois. I watched last week as an American robin (Turdus migratorius) plucked dried grasses from the yard, nudging them into place with her beak and wings, readying her cup-shaped nest for the azure eggs that are synonymous with spring. From the nearby American sycamore (Platanus occidentalis) tree, I heard the gurgling chatter of a flock of brown-headed cowbirds (Molothrus ater).

I thought about how while the robin might’ve seemed completely absorbed in her nest building, she was probably wearily listening to the cowbirds, too. Brown-headed cowbirds are North America’s most common avian brood parasite, forgoing nest building altogether. Instead, they lay their eggs in the nests of more than 200 other species of birds, leaving the incubation and rearing of their young to these unwitting foster parents.

A female brown-headed cowbird (Molothrus ater) spotted at Rollins Savanna in Grayslake. Photo © Phil Hauck.
A female brown-headed cowbird (Molothrus ater) spotted at Rollins Savanna in Grayslake. Photo © Phil Hauck.
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The curious courtship of the American woodcock

Post by Jen Berlinghof

March is the demarcation of spring. This new season is brewing now as snowmelt percolates through the thick mats of leaves on the forest floor into swollen creeks. Sap is rising in the sugar maples (Acer saccharum), with its promise of sweetness after a harsh winter. The purple, mottled crowns of skunk cabbage (Symplocarpus foetidus) peek out of the thawing mud, surging toward the sun. And the quiet of winter is replaced with the cacophony of western chorus frogs (Pseudacris triseriata) accompanied by the “peent” and “whir” of American woodcocks (Scolopax minor) in the Lake County Forest Preserves in northern Illinois.

The American woodcock (Scolopax minor) is a curious species to study. Stock photo.
The American woodcock (Scolopax minor) is a curious species to study. Stock photo.
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On the path to recovery

Editor’s note: hello readers, Brett Peto here. Guest author Pati Vitt, Manager of Restoration Ecology at the Lake County Forest Preserves in northern Illinois, is back with the second of her three-part series about our research project to restore 180 acres of former farmland within Grant Woods Forest Preserve using a climate-adapted, regionally sourced native seed mix.

An aerial view of the 180-acre research project area at Grant Woods in Ingleside. Photo © Mike Borkowski.
An aerial view of the 180-acre research project area at Grant Woods in Ingleside. Photo © Mike Borkowski.
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Flicking through the Flickr pool

This gallery contains 10 photos.

Post by Brett Peto

You don’t need me to tell you that 2020 has been a long year. In a pandemic, separated from routines, sometimes days go slow but months go fast, and vice versa. There are fewer anchors around which to pin our schedules like so many pieces of laundry on a clothesline. Some people have started baking homemade bread, assembling model kits, binging movies and podcasts, devouring piles of books, or playing long-distance board games over Zoom. Our strategies may vary, but I think it’s helpful to have as many coping mechanisms as we can gather this year.

One adopted or continued by many folks is spending more time outdoors. Whether in yards, neighborhoods, parks, or the Lake County Forest Preserves in northern Illinois, people are discovering or rediscovering the value of nature, even as the thermometer dips. Fresh air; sunshine; wide horizons; the sounds of wind in trees and water over rocks; birds and squirrels and foxes living their private lives; the calm curiosity to find out where a trail goes and the confidence that it’s designed to go somewhere.

"Ice Ice Baby." Photo © Michelle Wendling.
“Ice Ice Baby.” Photo © Michelle Wendling.
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Growing through change

Editor’s note: hello readers, Brett Peto here. This month, we’ve opened up the floor to guest author Pati Vitt, Manager of Restoration Ecology. She’s here to discuss a recent virtual workshop we held as part of our research project to determine best seed sourcing practices for climate resiliency.

“We know that by 2050, our climate is predicted to be more like Oklahoma,” says Pati. So, we need to understand whether we should source seeds from further south to make our restoration projects more resilient to climate change. To help determine this, we’re procuring 800 pounds of native grass seed from southern Illinois and Kentucky.

This November, we’ll plant those seeds in 180 acres of former agricultural fields at Grant Woods in Ingleside. Then we’ll monitor and compare each species’ growth to seeds sourced from our area. I’ll let Pati pick it up from here.

A portion of the research project area at Grant Woods. Photo © Lake County Forest Preserves.
A portion of the research project area at Grant Woods. Photo © Lake County Forest Preserves.
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The feathered friends of fall migration

Guest post by Ken Klick

Fall bird migration is happening now at the Lake County Forest Preserves in northern Illinois, and each day (and night) brings tens of thousands of newly arrived birds. Yet finding fall migrants can be challenging. Their subdued palettes of brown, tan, and olive feathers hide in sharp contrast to their resplendent springtime colors.

Unlike spring migration, most birds travel quietly in the fall, barely whispering a note to indicate their presence. In Lake County, fall migration starts in July, when our forests and prairies are green and full of blooming flowers. It’s a five-month-long period involving more than 200 species that rest and feed in our nearly 31,000 acres of preserves.

Spotting a bird can be difficult when vegetation conceals fleeting glimpses, making observations tricky and identification nearly impossible. Besides, who’s thinking of fall migration in July’s summer vacation mindset?

Either way, here are some of my favorite fall birding observations by month, over my past five decades of birdwatching.

July brings our first fall migrants: shorebirds. A visit to the Lake Michigan shoreline at Fort Sheridan in Lake Forest finds sanderlings (Calidris alba), sandpipers (Scolopacidae family), and yellowlegs (Tringa spp.) avoiding people and surf while searching for food. Many migrating shorebirds have just finished raising young in the tundra’s perpetual daylight and have embarked on a 6,000-mile round trip journey.

Solitary sandpiper (Tringa solitaria). Photo © Phil Hauck.
Solitary sandpiper (Tringa solitaria). Photo © Phil Hauck.
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