Canadian Tiger Swallowtails

While we’d been busy banding birds, the Sun had climbed high into open skies above the Moquah Barrens on the spine of the Bayfield Peninsula. The temperature had climbed since early morning, too. As the group of students in the Wisconsin Master Naturalist Volunteer Training Course climbed back into our cars and caravanned through this U.S. Forest Service Special Management Area, yellow clouds rose up from the middle of sand roads.

Pulling into the Bladder Lake Recreation Area a few miles away, we were met by more yellow. Kathrine, one of the Museum’s new Summer Naturalist Interns, walked down to the sandy shoreline only to be engulfed in a swirl of yellow wings. I don’t think I’ve ever seen more Canadian tiger swallow butterflies in a single day!

This abundance of beauty has been building. On June 5, as I paddled the Namekagon River for a “Birding by Ear” field trip, occasional tiger swallowtails flitted along the shoreline. By June 10, we encountered half a dozen on the blackberry flowers at the trailhead for Morgan Falls—a hike that’s always a highlight of the Master Naturalist Course. And now it was June 11, and we were surrounded by their delicate yellow wings with black tiger stripes and scalloped edges leading into two little “swallowtails” at the rear.

As lackadaisical as the flight of butterflies may look, these butterflies are in a hurry to complete their life cycle in a brief northern summer. Visiting flowers to sip sugary nectar powers their flight. Males need some additional nutrients, too, and those come from something much less sweet than a flower.

Our vehicles disturbed clusters of butterflies on the sand roads. Their rising inevitably revealed a pile of animal scat. Male butterflies engage in an activity called puddling, where they lap up nutrients from the surface of puddles, or piles of poo. At Bladder Lake, they were puddling on a collection of decaying plants that had washed into a corner of the beach. The salts, proteins, and minerals they gain from this behavior get wrapped up in a nuptial packet and transferred to the female during mating.

Most if not all male butterflies engage in puddling, but it seems especially important for Canadian tiger swallowtails. Females must have enough energy to give their offspring a head start by laying large eggs; the nuptial packets are part of this. They also place their eggs, one per leaf, on the south side of trees. This provides more warming Sun exposure and less competition for the developing larvae.

As the temperature increases from 54 to 86 degrees Fahrenheit (due to normal changes in weather, or just a great location) the larvae can increase their growth rate by up to 500%. There is a catch, though. Larvae on birch trees won’t grow faster, even if it’s warm. Only the more nutritious leaves of aspen trees allow for such rapid growth. The butterflies must choose their host plants carefully, and hope that aspens are available, especially at the far north end of their range in Alaska and Canada. Apples and cherries are also possible host plants.

In a surprising but smart move, if a caterpillar survives a summer cold spell, they will then begin to grow faster. The longer and the colder it was, the faster the caterpillar will grow when it’s over—as long as they aren’t dead. Larvae with food in their guts freeze at warmer temperatures.

With all the poop puddling their Papas do, perhaps it’s fitting that young tiger swallowtail caterpillars avoid predation by looking just like brown and white bird droppings as they feed on the sunny surfaces of leaves. The older caterpillars costume themselves to look like mini snakes with leaf-green bodies and big yellow eyespots. They arm themselves with orange glands that emit stinky chemicals if disturbed. Despite those defenses, birds such as the gray catbird, rose-breasted grosbeak, and eastern towhee who we’d banded earlier that morning, probably eat many of them. As we’ve discussed before, one Being’s baby is often another’s baby food.

If they survive childhood, the larvae store up cryoprotectants to help them avoid freezing and then transform into pupae. Once properly hardened off and hidden away, the chrysalis can survive at least seven consecutive days at -2 degrees. The faster that a caterpillar can get to the safety of a cold-hardened chrysalis, the better—even if that means not growing as large. Smaller larvae result in smaller adults, but that didn’t seem to matter to the clouds of yellow and black butterflies rising in the sunshine.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too. Natural Connections 3 is in the works—and needs illustrators from the community! Find out more at: https://www.cablemuseum.org/books/

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our Summer Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Junebugs and Beetles

Something small and bright caught my eye. Stopping mid-stride and mid-conversation, I bent down to look at a small jumble of legs and exoskeletons in the tread of the Ice Age Trail. Luckily, my hiking buddy was also a naturalist, and she investigated the insects with me.

The yellow mantle behind the head of a black carrion beetle is what I’d noticed first. They are quite striking, even when rooting around in the decaying flesh of a recently dead animal, looking for a place to lay their eggs. The adults eat dead stuff, too, hence the bear hug this one was giving a shiny brown, but unmoving, carcass of a Junebug. I snapped a couple photos of the food chain in action, and we continued hiking.

Seeing the Junebug triggered childhood memories of these big bugs battering against the window screens while we played board games around the kitchen table on hot summer evenings. Though harmless and clumsy, their clawed feet and loud scrambling scared me. Things scritching on windows at night was definitely the stuff of nightmares.

Junebugs are harmless of course. And they are not actually bugs, they are beetles in the genus Phyllophaga, which means plant eaters. The distinction between bugs and beetles has to do with their wings. True Bugs have one pair of wings that are half leathery and half membranous. When folded, they don’t quite meet. This forms an X on their back. Stink bugs are a classic example. Beetles, in contrast, have two pairs of wings. One pair is hardened into a protective sheath, and they cover a more fragile pair used for flying.

Well, the males use them for flying anyway. In many species of Junebugs the females have small, ineffective wings. Instead, they waft pheromones into the night and let the males come to them. Sometimes the males get distracted from their search by your lighted windows. Now that the air conditioner is turned on and the windows closed, I rarely hear them.

The next afternoon I was walking dirt paths again, this time at the Cable Community Farm. A glint of shiny auburn caught my eye, and once again I was looking at a dead Junebug in the dirt. Their particular shade of red-brown really is very pretty. I think Anne of Green Gables would approve. Their head had been snapped off and the guts extracted through the hole. No murder weapon was in sight.

Since my evenings at the garden have been alive with birdsong, an avian predator was my best guess. Birds are excellent pest control at the garden. Bluebirds love caterpillars, tree swallows clear the air of flying insects, a local Cooper’s hawk will hopefully keep the rabbits out, and someone ate a Junebug. Thanks, Friend!

Junebugs are native insects, but in large numbers they can be destructive to lawns and gardens. Their larvae are big white grubs who live in the soil for a few years while nibbling on the roots of plants. The damage makes it hard for plants to take up nutrients and water, so they end up looking yellow and wilted. Robust, healthy plants can often withstand the stress, but small plants may be killed.

I dropped the Junebug’s empty shell back to the ground and continued with my task for the day—hand sifting the soil in an entire row to pick out rocks and make it ready for carrots. The Cable Community Farm is enjoying our first year at a brand-new site, and the soil has already grown a bumper crop of rocks!

Partway through the row, that familiar shiny brown popped up again. This time the Junebug was still alive! As I pulled out my phone to snap some photos, the beetle ran around anxiously until they found soft soil and then made short work of burrowing back down. It was clear that they prefer being underground during the day, even as adults. Zooming in on the photos, I could see the little clubs at the end of their antennae that are characteristic of the Scarab Family. These can be fanned out to detect odors.

After finding only one live beetle in my garden row, I was happy for my carrots, but worried for the Earth. Many people are quick to pull out the chemicals when they see an insect but fail to see the far-reaching consequences of disrupting the food web. Decades of increasing use of pesticides has taken a toll on ecosystems, and the beneficial bugs—like pollinators—often are killed right alongside the ones whose value we don’t yet understand.

I dug the beetle back up and tossed them into the compost pile with the grass roots, far away from my carrots. They are an important member of the ecosystem and I’m happy to let them live…over there.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too. Natural Connections 3 is in the works—and needs illustrators from the community! Find out more at: https://www.cablemuseum.org/books/

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our Summer Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Skydancing the Night Away

Excitement and nerves were at an all-time high as my car crept down the gravel road, the sun having just slipped below the horizon. I was on the hunt, following clues to lead me to my prize. My treasure was the somewhat elusive American woodcock, and I was hoping to catch a glimpse of their infamous skydance. Each spring, the males put on a dramatic display to attract a mate. They prefer a wet, forested area to hide out in, with a clearing nearby to perform their dance. The spring peepers and chorus frog songs that filled the air clued me in on being in the right place.

An American woodcock. Photo by Keith Ramos, USFWS.

The wind whipped through the trees, and time ticked by as robins, chickadees, and other songbirds sang their evening delights, but I had yet to pick up on the distinctive call of the American woodcock. Doubt began to creep in with each minute that went by. I began to wonder if I had found the right place, and was on my way to accepting that I may not find what I was searching for tonight. That's when I heard it–the American woodcock's opening line to start his show.

Peent.

My head snapped to the direction of the sound, with my ears tuned in and excitement taking hold once more. There it was again, peent. The soft, almost nasally call was off in the distance. I started my car and continued creeping down the gravel road. A small, shadowed shape flashed before my car, and disappeared into the thicket on the other side of the road. A woodcock!

The woodcock landed on the gravel road, not 20 feet behind my car, and began to call out again. Peent. I watched his silhouette, barely letting a breath escape my lungs, not wanting to risk scaring him away. He continued his serenade for a few more minutes before rocketing into the air. The remaining light was dwindling fast, but I watched as he flew past and began his spiral upwards.

As he flew, I mainly tracked him with my ears–only catching an occasional glimpse with my eyes. The twittering noise of his wings gave him away, his physically modified flight feathers singing as air rushed through them. It was like being immersed in a natural surround sound theatre as he circled around, higher and higher, the whistling sound of his wings looping through my ears.

Suddenly the sound of his ascent stopped, and a new sound took its place. In the final act of his mating display, the woodcock fell from the sky, spinning acrobatically as he plummeted. I found it reminiscent of scenes in old cartoons with the twittering piano tunes escalating as the character falls through the air. But rather than crashing into the ground, he righted himself at the last moment, and landed near the same spot he took off from. He was hoping that a female had taken notice of his superior showmanship, and would be waiting in the spot he took off from. He was not so lucky this time around.

But rather than that being the end of the show, it's simply the first act of many. As he stood on the gravel road that was his stage, the Woodcock began to call again. Peent. His determination to impress the ladies will keep his show going into the night.

While I was not his intended audience, I was enthralled by his skydance. There is something to be said about being privy to the intricate lives of wildlife. It feels intimate, getting a small glance into their private lives. As I watched the woodcock’s dance, a few cars drove down the gravel road, but turned before reaching us. I couldn’t help but think they were so close to a show of a lifetime, and had no idea. The woodcock paid them no mind, continuing to call out before taking to the skies again.

Night had completely fallen by the time I headed home. As I left, I was grateful I witnessed the woodcocks skydance. It is amazing how the smallest moments leave lasting impressions, and the impactful memories that wildlife can impart. I wish I could thank him for letting me witness his display, and the lasting memories he unknowingly imparted. Instead, I left him still singing on the gravel road and wished him luck in his nighttime endeavors.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our Summer Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Baby Food

The wetland just east of Lake Namakagon was still brown with last year’s dried leaves and swollen with this year’s melted snow as we drove home from a chilly hike in late April. Movement caught our eye, and we peered intently into the late afternoon sunshine. Two sandhill cranes, perfectly camouflaged in the warm browns of the marsh, stood on a spit of sedges and leatherleaf. Their red caps didn’t stand out, but when their eyes caught the sun just right, they glowed orange.

As we watched, one crane and then the other dipped their head down into the thicket of plants, then tossed a twig or long leaf over their shoulder. Over and over they repeated this behavior while we snapped photos. At one point, one of the cranes folded up their stilt-like legs and nestled their belly into the vegetation, their long black beak, red cap, and orange eyes just visible over a small channel of open water. Clearly, they were building a nest. Likely, the sitting bird was the female, helping to mold the pile of weeds into a cozy home.

Although the female shapes the nest and incubates the eggs overnight, the male helps to build the structure and splits incubation duties with her 50/50 during the day. Both parents lose belly feathers to form a brood patch where blood vessels just under bare skin share body heat with the eggs.

Although I often hear their rattling bugle calls echoing across the lake and through my open windows, having cranes nest where I could see them was a new treat. For a few weeks, every warm afternoon found me biking along that stretch of road with my camera at the ready. Each time, the evening sunlight spotlighted the face of a crane on the nest.

Then, I left for a conference in California. When the weather and my schedule finally cooperated again, it had been exactly a month since the nest building. Although I scanned the wetland with high hopes, no cranes were visible. The typical incubation period for cranes is 28-30 days, so it was conceivable that the 1-3 eggs might have hatched. But although the chicks emerge with eyes open and can soon walk and run, there’s little chance they could have already had the strength to travel to another wetland. And although they would have been too small for me to spot among the shrubs, their parents would surely have been visible.

The possible culprits are numerous. Many Beings will eat an egg or a baby bird. Crows, ravens, raptors, foxes, coyotes, raccoons, mink, and great horned owls are all potential predators if they can avoid the kicks and stabs of a defensive parent.

A few days after biking past the empty wetland, I switched vehicles. Paddling through a wide, marshy section of the Namekagon River, we again spotted a pair of sandhill cranes. This time their rusty feathers stood out against the fresh green spikes of horsetail. One stalked through shallow water with eyes focused downward, even dipping their head into the muck for something tasty.

The harsh cries of a red-winged blackbird brought our attention back to the other crane in the taller grass. The red and yellow epaulets on the blackbird’s wings flashed brightly as he dive-bombed the crane and even landed on their broad brown back. The wading crane returned, but there was little they could do except hunker down and point their beaks against the attacks of the smaller bird.

And could you blame him? This one male blackbird may have attracted as many as 15 females to build nests in his territory. While he doesn’t help incubate the eggs like the male crane, he does spend more than a quarter of his daylight hours in territorial defense against his peers and potential predators. And the cranes were potential predators. Although they eat plenty of waste grain from farm fields during migration, throughout the breeding season they seek the protein of small mammals, frogs, and baby birds. The blackbird was right to be leery.

These crane encounters drove home an ecological reality: One Being’s baby is often another’s baby food. The abundance of summer is driven by this necessity. Tender young leaves become caterpillar food. Six thousand caterpillars—who are baby butterflies and moths—become a half-dozen chickadee chicks. Some of those chicks become red squirrel kittens. The squirrels become red fox kits, and so on. How does anything survive?

Red-winged blackbirds can have multiple broods with several eggs over the course of a summer. Even after feeding a few cranes, they are one of the most abundant native birds in North America. At best, a pair of cranes raise no more than one chick per summer, but may have 30 years or more together to produce two successful heirs and replace themselves. Even with some predation, their population is increasing slowly due to habitat protection. There is space enough for all of us.

In the end, we can’t escape the fact that a bit (or a lot) of death goes into every life.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our Summer Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.