Ripples 12/9/21

Posted on by December 10, 2021

Ripples from the Dunes, by Kennedy Zittel, Assistant Naturalist

Woodland Dunes does bat surveys every year to see what bat species are around our preserve and how many of each species we come across. Recently during these surveys, we have discovered that this area has a large population of bats, which is wonderful! This large amount of bats is likely due to the large number of resources located here (and a healthy insect population too!). Bats are great! They are the only flying mammal. They use echolocation to help them see in the dark. And one single bat can eat up to 1,000 insects in an hour. That’s a lot of mosquitoes! Now that it is colder out… what happens to our bats during the winter?

photo of eastern red batBats are classified into two groups depending on how they choose to spend winter. There are the tree bats – those that roost in trees and migrate in the winter. And there are cave bats – those that hibernate in caves and mines during the winter. In Wisconsin, the tree bats are the silver-haired bat, hoary bat, eastern red bat, and evening bat. In Wisconsin, the cave bats are the little brown bat, big brown bat, northern long-eared bat, and the eastern pipistrelle. 

Tree bats commonly roost in trees. These bats will begin to migrate as early as September. They will seek out areas with a warmer climate than where they are leaving from that also have an abundant food source (insects) to help them make it through the winter season. For example, hoary bats, which are some of the most common bats to see here at Woodland Dunes, will travel south and gather in large groups along the US coast and in Northern Mexico. 

Cave bats spend winter going through a cycle of torpor followed by periods where they are awake with a raised body temperature (depending on the weather). Torpor involves physiological changes such as changes in body temperature and metabolic rate that allow the animal to survive periods without food. During the winter a bat’s breathing rate, metabolic rate, and heart rate are all reduced. By reducing these rates a bat can reduce its energy costs by 98%! During this time a bat can go minutes without breathing and its body temperature can drop to near freezing. The bat’s heart rate can also drop from 200-300 beats per minute to only 10 beats per minute! How crazy is that? Bats choose places like caves, mines, natural fractures in rocks, and other structures like that due to their constant temperature levels and humidity. The location where a bat hibernates is called a hibernaculum. 

One big issue that has been devastating the cave bat populations is a disease called white-nose syndrome. This disease is caused by a fungus  (Pseudogymnoascus destructans) that thrives in cool and moist conditions of caves and mines. This fungus infects the living tissues of the bats and causes them to wake up out of torpor too early. By waking them up too early it causes the bats to use up their fat reserves too quickly which starves the bats. Once a cave is infected with the fungus there is a 95% mortality rate of the bats within the cave. Currently, there is no cure for the disease, though scientists are working hard to find a way to stop the disease before it kills off more of the cave bat populations. 

We humans often talk about how important our pollinators are and how we need to protect our pollinators, however, it is often forgotten that bats are pollinators too! They pollinate things like bananas, mangos, guavas, cacao, dates, figs, cashews, and peaches. Our nocturnal pollinators are just as important as the daytime ones, and bats need our help. Next time you see a bat, instead of being spooked by it, think about how many mosquitoes that little bat is going to eat in just that night alone, and how bats are cool creatures worthy of our love and support.

photo- eastern red bat at Woodland Dunes, photographed by Bob Randerson in spring 2021

Ripples 12/2/21

Posted on by December 2, 2021

By Kennedy Zittel, Assistant Naturalist

Now that the weather has gotten colder, we have begun to say goodbye (for now) to some of our animal friends here at Woodland Dunes. With the cold comes hibernation, and one of our hibernating friends is the woodchuck! Woodchucks (Marmota monax) are large rodents that belong to the squirrel family. On average woodchucks are 16-27 inches from the tip of their nose to the tip of their tail and they can weigh roughly around 10 pounds. Woodchucks are diurnal, meaning that they are awake during the day, so when they are not hibernating we often get to see them around the nature center buildings. The ones here spend their days sunning themselves on the boardwalk behind the barn, sitting on top of the deck railing to get a better view, and occasionally climbing into the bird feeders to munch on seed. And to be honest, since it happens infrequently it is pretty comical watching the round rodent try to squeeze into the little bird feeder. Making the 3 foot climb to the birdfeeder is no trouble for a woodchuck, in fact, they are actually very good climbers and can even be commonly seen sitting up in trees. 

Staying within a few hundred feet of their dens, woodchucks will only travel long distances to search for food or to find a mate (mating season for them is March-April). Young woodchucks will only stay a short period with their mom, and leave the den mid-July. Hibernating October to March, woodchucks have to spend the rest of the months building up fat reserves to help them survive sleeping through winter. Contrary to their name, woodchucks have very little to do with wood. They mostly feed on a variety of fruits and green plants, with the occasional flower, insect, and tree bark. Their name doesn’t refer to wood at all, instead it is derived from the Algonquian word for them, wuchak. 

Often people refer to woodchucks as “pests” but really they are just trying to live as they normally do in an ever-shrinking habitat. As we humans continue to spread out we will just have to learn and appreciate coexisting with the wildlife that was already here.

Woodchucks play an important part in the local ecosystem. In addition to being food for other animals, they provide farmers and gardeners with some helpful things. When they dig, woodchucks aerate the soil allowing for plant roots to get oxygen. The digging and burrowing also helps to mix up the soil so plants can absorb nutrients that they wouldn’t have gotten otherwise. Organic matter accumulates on the top of the soil whereas other nutrients like calcium, iron, and phosphorus often sink deeper into the soil with rainwater, so by digging, those nutrients can reach the plant roots closer to the surface and the organic matter can sink deeper for things like earthworms to munch on. Their burrows also provide homes for amphibians, reptiles, chipmunks, and other small mammals after the woodchucks have left. One cool thing is that even when woodchucks are still using their burrows and dens, other hibernating animals will go into one of the burrow rooms for the winter! This means that other animals like possums, raccoons, skunks, and rabbits can all be roommates with woodchucks over winter. 

Now, if that isn’t enough reasoning for why they are neat to have around, woodchucks are also responsible for two major archeological discoveries! In Ohio at the Ufferman Site woodchucks unearthed countless artifacts that were from a Cole Native American village. In Pennsylvania, a woodchuck unearthed artifacts that helped scientists discover the 19,000 year old Meadowcroft Rockshelter site – which is the oldest evidence of humans in the Americas ever found. 

Not only are woodchucks good for the soil and other animals, but they have helped us understand more about our history. So the next time you see a woodchuck digging around, instead of being upset over it, think of what it is doing for the soil, and perhaps check out the area after it leaves. As you never know what cool discoveries those little furry archeologists may dig up. 

photo of woodchuck in feeder by Kennedy Zittel

Ripples 11/24/21

Posted on by November 24, 2021
The things for which I am thankful may be slightly different than those of most people, based on experience.  Yesterday when we were banding birds at the nature center, I was grateful to hold a small, soft, warm junco in my hand as I measured it and placed the band on its leg.  Then I was thankful to release the bird and watch it fly into the nearby spruce trees- it did not belong to me and it needed to be free to spend the winter here before migrating back north in the spring to nest.  When you feel the vibration of its rapid heart beat and look into it’s deep brown eyes you realize that it is a being unto its own, and that your encounter with it is a fleeting gift which can be held in length only in your memory.  Our hope is that someday against the odds someone else will also hold this bird, and tell where it traveled and how long it lives.

photo of forest floorIf you are thoughtful and aware, you realize that this one bird is a very small part of an enormous ecosystem filled with many other beings- animals of all sorts, flowers, trees, fungi- all playing a specific role in a very big world.  But not infinitely big- we’ve demonstrated time and time again how we, above all other creatures, can foul things up.  But in many cases, given just a little encouragement and repair, nature seeps back in to at least try to re-establish its former self. 
 
Nature starts with plants, and establishing even a small patch of native plants will provide a home for insects or other small creatures, and by linking such places we can build habitats that can become landscapes, even if we are living there, too.  People who recognize the value of such places, the plants and the animals, provide a service to others both human and non-human.

I won’t be banding birds on Thanksgiving, but I will plant the last few trees of the year.  And while I do so I’ll think about my family, the people in our community who appreciate trees, the people who support our nature center, and the beings of the forest we are working to re-create.  With the hope that we can better learn to appreciate both each other and nature as well.      

 
 

Ripples 11/18/21

Posted on by November 18, 2021

Ripples from the Dunes, by Kennedy Zittel, Assistant Naturalist

On warm days here at the Dunes it isn’t uncommon to see a common garter snake basking in the sun alongside the trails. Common garter snakes (Thamnophis sirtalis) are some of the most abundant snakes throughout the eastern portion of the United States. They live in a wide variety of habitats such as meadows, woodlands, marshes, hillsides, edges of lakes/streams/ponds, and are common in urban areas too. 

Garter snakes are variable in color pattern but typically have three light colored stripes that run along the length of their body. They can even grow to be five feet long! Though males are typically smaller than females are. Garter snakes eat earthworms, amphibians, slugs, snails, insects, crayfish, small fish, and small snakes. To avoid being eaten, they rely on camouflage. Their stripes make it difficult for predators to see them amongst the grass. If spotted they will flee into water to avoid land predators. If they cannot flee, they can strike and bite though they aren’t venomous. If you have ever picked up one though you may also know that if grabbed they will release a foul-smelling secretion to deter predators. Yuck!

Now that the weather is colder…what happens to the snakes? Common garter snakes hibernate late October through March. Since they are cold blooded, their hibernation is called brumation. If the weather is warm enough though they will wake up to sun themselves outside. Since the snakes have no arms, using a shovel would be pretty difficult, so instead of digging their own hibernation space they use natural cavities (fallen logs, stumps, under rock piles) or will use old animal burrows. 

Sometimes hundreds of snakes will hibernate together in large groups to help stay warm. This hibernation space is called a hibernaculum. Lying together prevents heat loss and keeps the snake’s body temperature from dropping too low. Since they are cold blooded, snakes lack the ability to generate body heat internally. Instead they rely on external sources to help regulate and maintain their body temperature. This is why garter snakes bask in the sun to help maintain their body temperature (to around 85 degrees Fahrenheit). 

While they are hibernating, they can absorb moisture through their skin, however, they cannot eat during this time because their body temperature is too low to digest food. Like other hibernating animals, snakes will build up fat reserves to help them make it through winter. Once the weather warms up and spring comes around the snakes will emerge and bask in the sun alongside the trails once more.


photo- baby garter snake by Kennedy Zittel

Ripples 11/11/21

Posted on by November 12, 2021

By Kennedy Zittel, Assistant Naturalist

Psithurism: The sound of the wind in the trees
From: Greek word “Psithuros” meaning to whisper
Pronounced: “sith-err-iz-um”

For nature lovers, the fall is both wonderful and sad all at once. A season of hellos. A season of goodbyes. A season of changes. In the fall we say hello to migrating birds that are either just passing through or those that choose to come and stay here for the winter. In the fall we also prepare to say goodbye to many of the creatures we grew accustomed to seeing each day as they prepare to sleep throughout the cold winter. The green leaves we grew used to seeing above our heads and alongside us as we walked the trails are now turning shades of reds, oranges, yellows, and purples. The grass that used to grow green now turns to different shades of brown under our feet. Though this season is a whirlwind of changes that seems to always fly by so quickly, it truly is one of the best times to hear the songs of the forest.

Taking a stroll through the forest in the fall allows us to hear the psithurism of the trees around us. Those leaves that are now a  sunrise color palette overhead begin to turn brittle and cling to the branches with an ever-decreasing strength. When the wind blows through the branches the leaves change the volume from a once soft whisper to a loud rustling noise. This increase in volume begins to turn a walk through the forest into an almost musical experience. The wind howls its own portion of the fall song while it helps the leaves rustle and rattle in the branches above. With every step you take you add to the music with soft crunching noises that we associate so well with fall.

Animals like squirrels and rabbits scurry through the fallen leaves looking for the last bits of food before the winter. Birds that are migrating through change up the forest’s song each day. Depending on who is singing, the songs from the brush alongside the trail can vary day by day. The last of the frogs croak and peep one last time before they make their beds below the leaf litter until spring. Acorns and pinecones fall to the ground from the sky above with soft thumps as they land at the base of the trees, just waiting to be carried away by a hungry animal. The once green grass turns to shades of brown and whooshes in the wind.

As the season progresses the wind begins to blow with a stronger force. The once loudly rattling leaves now turn into a decrescendo of rustles until they all soon fall to the forest floor. The animals that were once scurrying around are now asleep in their winter homes, not ready to make a noise until spring comes. The birds are done migrating through, and those that are left are here for the whole winter. Creating a more steady song in the forest. Frogs are now underground waiting for spring to thaw them out before they begin their song again. The conifer trees held onto their modified leaves and continue to do so as the wind whistles softly through their branches. Though one might think that the end of fall has brought a grand pause in the forest’s music, it has merely just created a new song for the time being. You can still hear the forest whisper and sing as you walk, just a different more soothing song as the blanket of snow covers the ground and ice crystals cling to the branches alongside the trail. Regardless of the season, it is always good to go out and listen to nature around you, as you never know what kind of concert it is ready to put on until you get out and listen.