Ripples from the Archives submitted by Nancy Nabak, communication coordinator
This week’s Ripples is an excerpt from the Winter 2003 Dunesletter Field Notes, written by Jim Knickelbine, then Director of Finance and Naturalist. Learn how nature prepares for the upcoming winter.
“As we button up ourselves and our homes for winter, I think about the many different strategies our fellow creatures employ to survive this cold, dry time of year, and how some of those preparations began many months ago. Those creatures that can’t make or find enough food must either migrate or reduce their consumption through some kind of dormancy.
Deciduous trees make too little food in the low light of winter and lose too much water to make maintaining their leaves profitable – it’s better for them to start over in spring (although root growth can occur for much of the year). The trees we term evergreen, although they regularly replace their leaves, have a waxy coating that reduces moisture loss, and permits food production when conditions are favorable.
Animals have various kinds of dormancies. When rescuing our goldfish from a small outdoor pond, I found a leopard frog in a dormant state at the bottom. It appeared to be covered with a milky substance, which may have been very fine silt. Brought inside, and very gradually warmed up to room temperature, it returned to an active state. It is now a winter resident at the Nature Center and will be released after our spring wetland program.
Not all frogs spend the winter in a watery repose. Wood and gray tree frogs burrow under the ground layer of leaves or just below the surface of the soil. Their livers produce large amounts of glycogen (a form of glucose), which is rapidly pumped throughout their bodies. This process is triggered when ice crystals start to form in their feet and prevents cell damage due to freezing. The amount of glycogen in their cells, which would be fatal to us, allows these frogs to literally freeze solid and still survive.
…My yard seems to come to life in winter. During snowless months, I am only vaguely aware of nighttime activity outside my door: frogs singing in spring, an occasional owl, perhaps coyotes, certainly crickets. But come the first snowfall, I’m amazed at the number of deer mice, cats (I don’t remember actually seeing any cats lately), and possum crisscross the yard each night while I snooze unaware! After daybreak, birds, squirrels, beagles, and my own nestlings add their prints to the ever more tangled web in the snow. Then, a fresh dusting and the pallet is ready for a new design. The dead of winter is anything but that – I tip my hat to all those who survive the season outside without one!”
photo by Nancy Nabak
By Jim Knickelbine, volunteer
As we approach the date of the founding of Woodland Dunes 50 years ago, we also remember that bird research in what is now the preserve began a decade before that. Bernie Brouchoud and others caught and banded thousands of songbirds and raptors starting in the mid 1960’s, and that practice has continued uninterrupted to this day. In doing this, Bernie discovered that northern saw-whet owls aren’t a rarity, but in fact, are frequently found migrating to and through this area, although they are seldom observed. Bernie developed an extensive banding program with dozens of volunteers who checked nets throughout the night during the migration period. Banding practices have changed, resulting in a more limited and careful approach to banding, which we continue to this day.
Banding saw-whets is an interesting and challenging task. The birds migrate through our area at the beginning of to mid- October, and the migration peaks late in the month. We continue to try to catch and band birds until early November. We’re able to band several dozen owls each fall.
Experiencing the natural world at night expands the horizon of one’s understanding. To me, the world seems to come into a different kind of focus. Our vision is limited to fewer options- the landscape is dark except where it’s illuminated by our headlamp. The sky is dark except where the moon and stars shine. Every sound seems to be more noticeable- geese or cranes out on the marsh, the peep of an overhead songbird in migration, the rustle of a rabbit or scratch of a raccoon’s claws as it climbs a tree. Or the call of a saw-whet in response to the recording we use to lure them to our banding station. Other owls, too, are heard- the sad whinny of a screech owl, or the harsher screech of a young great horned owl.
The experience of nocturnal nature is a special one, traded for the coziness of indoors with television to instead entertain us. I am reminded of this each year when banding begins. This year, the temperatures have 
been mostly mild with few cold nights. Many nights have had southerly winds, unfavorable to owl migration. The numbers of owls caught are fewer, but the season has been rich in experience. Early on, we experienced an evening of bright auroras- I don’t know that we caught any owls but will remember that night just the same. As the month wore on, the moon progressed from full to waning, with the sky becoming darker just as comet C/2023 A3 was visible in the west for several nights, the first comet I’ve been able to photograph. Each night it rose higher in the sky and became fainter.
And for the first time we encountered a flying squirrel in the preserve, although we’ve suspected they were here all along. This one became entangled in our owl nets but, like the birds, was released unharmed.
Owl banding isn’t a public activity, and at our location is too unpredictable to do as a public program. However, the banding data we’ve gathered from more than 5,000 owls is used by researchers to determine their movements and life histories. The first owl we caught this year was banded a year ago in southern Ontario east of Lake Huron. It probably moved south last winter, then north into northern Ontario, and back south to the west of Lake Michigan. One wonders why.
The wondering is what motivates us to keep bundling up and heading out into the dark to experience as the owls do. It’s not an easy thing to do, but one that we find very much worth doing.
Photos: saw-whet owl after being banded and released, aurora borealis at Woodland Dunes, and comet by Jim Knickelbine
By Sue Crowley, executive director
Happy Halloween Ripples Readers! This year’s Halloween is turning out to be wet and overcast with plenty of winds blowing the leaves through open areas, yards, down the trails, and beyond.
I was driving up I-43 toward Green Bay yesterday, and it struck me how many trees I had noticed that had shed most of their leaves except for some clusters on the very tops of the trees. Now you know you are following a forester, a birder, a wildlife watcher, or plant enthusiast when the car in front of you seems to be suspect in either maintaining a consistent speed or veering slightly outside of its designated lane. The reason is this (me included): we tend to practice “moving-vehicle-tree-identification” (or of whatever natural element has caught our eye)! One loves a challenge at 70 mph. Anyway, the trees I noticed were most likely cottonwoods or aspen (also known as popple). They looked a bit like candles with the flickering yellow leaves on top resembling flames.
I wondered why the leaves at the top had not dropped, while all the rest had made their way to ground. I honestly do not know the answer and found it curious to think that the top leaves seem much more exposed to the bluster of autumn than those lower down. One hypothesis is that these top leaves are most definitely sun leaves versus those lower down known as shade leaves. Sun leaves tend to be smaller and thicker. They do not need to be as broad to capture the sun’s rays, and they develop a thicker blade (the main part of a leaf) and perhaps the petiole (the leaf stem) that attaches to the tree. This thickness may mean it takes a bit longer to activate the cells in the abscission layer, which causes the leaf to leave the tree.
Well, that’s my story for this Halloween. Stay safe and enjoy the beauty of leaves all around.
Photo credit: Getty images, marekuliasz
By Jessica Johnsrud, education coordinator
With Halloween around the corner, I am reminded of some of the creepy, crawly creatures that live in our homes. There is one critter that definitely looks scary, but turns out to actually be one of the good guys. In fact, I recently heard this critter described by a scientist as, “an ideal roommate.” You may be surprised to learn that I am talking about the house centipede.
I understand their long legs are what give house centipedes a scary appearance. Scientists believe the human brain is wired to be afraid of centipedes and other multi-legged critters. Perhaps if we take a moment to learn more about them, we can move beyond their scary reputation and maybe even learn to appreciate them.
Let’s talk about those legs. House centipedes do not have 100 legs as their name implies. Instead, they have one pair on each of their 15 body segments. The legs are segmented (jointed) and this makes them appear to be much larger than they actually are. The body of the house centipede is only 1-1.5 inches long, but when you factor in the length of the legs, the creature is about 3-4 inches in length. The last set of legs are almost twice the length of the rest and look like antennae. If the house centipede is still, it is very difficult to tell which end is the head. This is called automimicry, when one part of the body imitates another, and is meant to confuse predators and potential prey.
Long legs are what help house centipedes be such impressive hunters. They prey on bed bugs, termites, cockroaches and other unwelcome visitors in your home. Their long legs and well-developed eyes allow them to have lightning fast reflexes. They are also sensitive to vibrations, which aids them when hunting. House centipedes have modified appendages in the front of their body for injecting venom into their prey, causing paralysis.
If I haven’t convinced you yet, female house centipedes exhibit maternal behaviors. They protect their eggs by curling their body around them and will continue to do this after the eggs hatch. The females even lick fungal spores off the eggs to keep them clean. What good mothers!
I know this all sounds a bit creepy, but if you think about it, perhaps house centipedes are the ideal roommate. They actively hunt and eat the truly scary bugs that can carry disease or cause damage to our homes. They care for their young and they do not like attention. They are rarely seen because they are active at night. They are even clean and do not spread disease, leave a mess or smell. When described in this way, I guess the house centipede isn’t so bad after all.
photo credit: wikipedia
By Max Kornetzke, land manager
Originally brought to North America as a quick growing hedgerow, common buckthorn (Rhamnus cathartica) is one of the more menacing plants you will encounter invading natural spaces across Wisconsin and the Northeastern part of the country. It has sharp thorny spikes, dark green, serrated, oval leaves, and inconspicuous green flowers in spring that lead to hundreds of dark blue-black berries in late summer and early fall. Seeds can be dispersed by birds, but they make for poor quality food. The berries produce laxative effects that help spread seed further into our natural areas. They’re also low in protein and high in carbohydrates.
If left alone, it will create dense monocultural stands with some individuals becoming small trees with scaly bark that look somewhat similar to the mature black cherry. It is also allelopathic, meaning it produces compounds that prevent other species seeds from germinating.
Recently, research out of University of Minnesota has helped dispel some common myths about common buckthorn, namely, that the seed bank is long lived. Researchers have found that once fruit bearing trees are cut and light is able to hit the ground, the majority of those blue-black berries will germinate within the first year, with the rest mostly germinating within the second. This is hopeful news for those looking to make an impact on buckthorn infestations and promote native plant diversity. With data that shows a shorter-lived seed bank, more people should feel encouraged to start working on what can seem like a daunting project.
If you’re interested, you can read more about this research here: Uprooting decades of buckthorn management practices: no long-lived seedbank | Minnesota Invasive Terrestrial Plants and Pests Center (umn.edu).
If you’re looking to offer food options that are healthier for birds and the environment, consider planting native shrubs and small tree species such as black chokeberry (Aronia melanocarpa), chokecherry (Prunus virginiana), elderberry (Sambucus canadensis), Service berries (Amelanchier sp.), or dogwoods (Cornus sp.).
Photo of common buckthorn by Ian Redding