Nature Blog

Ripples 4/15/21

Spring is a time for repair and improvement, and the nature center has been a very busy place lately.  Volunteers have constructed about 500 feet of new boardwalk on Willow Trail to permit hikers to more easily pass a section of trail that has been flooded more and more in the past couple of years.  Fixing and improving things seems to be universal this time of year- birds building nests, bumblebees enhancing their burrows so that they can lay eggs, mammals tidying up their dens for their new young.

Another project at the nature center involves replacing part of a deck next to the building, removing rotted boards that were close to the ground.  As the boards were taken up, we discovered a maze of tunnels beneath, and got just a glimpse of the animals that made them- star-nosed moles.

photo of star-nosed-moleThe star-nosed mole (Condylura cristata) is one of two mole species found at Woodland Dunes, the other being the eastern mole.  Both have massive feet and claws with which to excavate tunnels and burrows and both are harmless to humans.  They are covered with the softest fur- dark gray in color.  The nose of the star-nosed mole is adorned with fleshy tentacle-looking structures which help them feel their way around underground and detect the earthworms and other small animals on which they feed.  They have 22 of these unique structures, in which they have something called Eimer’s organs, and they are incredibly sensitive although strange looking.  Their sensitive nose structures allow them to very quickly determine if something is edible or not, and one study found that it took them only 227 milliseconds between the time they encounter prey and consume it.  Also, they are able to smell underwater, exhaling bubbles of air and them inhaling them again.

Star-nosed moles, although I imagine them leading quiet lives underground, are very active animals.  They have very poorly developed sense of sight, probably because there is not much that can be seen underground in the dark.  They spend much of their time burrowing in moist soil, and are often found in wet areas.  Its often in these wet places that we find the proverbial “mole hills” that they construct.  Mole hills are lumpy small mounds of soil made when the mole pushes up clumps of dirt to the surface from below.  They are small, typically less than a foot in diameter and just a few inches high, so it would be difficult to make a mountain out of one!  They are also good swimmers and look for food in the water, where they in turn may be eaten by fish such as northern pike.

Moles raise one brood of 4-5 young each year, typically in late winter or spring.  They have probably benefited from the photo of mole tunnels introduction of European earthworms by people (there were no earthworms in Wisconsin before settlement by Europeans).

Moles are not dangerous, and I cringe when I encounter people talking about the “damage” that moles do to lawns and how they need to be controlled.  Lawns are not a natural ecosystem, and moles do nothing more than hunt for small animals in the soil – occasionally making their mole hills.  Mole hills are not permanent and the moles move on, so there really isn’t a need to kill them.  They are an important native animal and should be appreciated as such.  They and their kind are unique among the mammals and probably do much more good than harm.  We’ll be careful not to disturb them more than needed as we re-assemble our deck!

photos: star-nosed mole by the National Park Service, mole tunnels beneath the deck at Woodland Dunes

Ripples 4/8/21

Written by Kennedy Zittel, Assistant Naturalist

The sun is shining, the days are warming up, migratory birds have begun to return…does this mean that spring is finally here? Even though this past winter was not nearly as bad as most Wisconsin winters usually are, I can’t help but wish for long warm days again. And the thought of being able to go kayaking again has really taken over any love that I have for the winter time.

photo of mourning cloak butterflyWith all of these springtime wishes fluttering around my head, seeing another thing actually flutter around my head has me feeling very optimistic. Often called the “harbinger of spring” the butterfly that I saw while walking along Willow Trail the other day certainly seems like a wonderful sign that spring has finally arrived. Fluttering along the trail was a mourning cloak butterfly. Mourning cloak butterflies (Nymphalis antiopa) are large butterflies that are native to Europe, Asia, and North America. With no similar looking species around, these butterflies are very easy to recognize. With dark maroon-brown colored wings, a pale yellow edging, and bright blue spots along the yellow edge, these beautiful butterflies get their name from their resemblance to the traditional cloaks worn by those that are in mourning. Though their name derived from such a sad sort of thought, these butterflies bring in happy thoughts of spring and warm weather to come. 

These butterflies have such an interesting life cycle, given that they do not (usually) migrate, and instead hibernate here over winter. If given the option, I am not too sure I would choose to stay under frozen leaf litter or in frosty tree cavities, but these butterflies do just that. Mourning cloaks will emerge from hibernation sometimes even before the snow has fully melted, which makes them one of the first butterflies that we see in spring. Their broods will emerge around July, then those butterflies will fly around all summer and fall, hibernate during the winter, those adults will emerge once the snow has started to melt, and then mate in spring. If that sounds like a really long life cycle for a butterfly, you are correct! Mourning cloaks have one of the longest butterfly life spans, given that they can live up to 11 to 12 months. 

The immature form of these butterflies are known as spiny elm caterpillars. These caterpillars also have a striking look to them, with black bodies, eight reddish-orange spots along their back, and their entire body covered in short hairs with black spines and white dots. Fully grown these caterpillars will reach around 2 inches in length. Upon hatching the caterpillars will eat the leaves on the plant that they hatched on. A large number of trees and plants have been documented having these caterpillars hatch from, including various willow species, American elm, hackberry, hawthorn, various birch species, wild rose, and poplar trees. The caterpillars will live together in silk nests on the host plant until they disperse before pupation.

The adult butterflies can be found in a variety of habitats, but are most commonly found in hardwood forests. The adult butterflies will feed on sap, ripe as well as fallen fruits, the sugars exudated from aphids, and very rarely they will feed on flower nectar. Though they are not overly helpful in terms of pollinating, these butterflies are wonderful to have around and are certainly a welcomed sight to see in the spring.

Photo by Kennedy Zittel

Ripples 4/1/21

The migratory flood gates are now open, and almost every day brings new bird sightings for the year.  No matter your interest, photo of male Golden-crowned kinglet there is a bird out there to match.  This week hawks are migrating along with turkey vultures.  On the waters there are more and more species of ducks and overhead tree swallows are returning.  In the forests, red-shouldered hawks have returned to their nesting places, and a variety of sparrows and thrushes are working their way among the shrubs.  On grasslands, meadowlarks, at least the ones that remain around here, are singing enthusiastically.

Birds seem to have different personalities.  Sandhill cranes appear to strut in a stately manner over fields,  mallards and geese graze peacefully on grassy fields and ponds, eagles peer seriously, looking over the landscape, and tree sparrows joust with each other before beginning their long migration north to the arctic.

One gets a more intimate experience if lucky enough to hold a bird in the hand, as we do when we are banding them to track their migration.  There are such differences in personalities between species of birds- tree sparrows and juncos are pretty mellow and easy to handle.  Song sparrows are feisty, and cardinals know how to use their large bills effectively, not hesitating to bite the hand that bands them.  The most ferocious are chickadees, which bite harder and more often than any other.  Perhaps being small, they have to try harder to survive.  But another small bird we find here has a much different personality, and if I were to nominate a species as being the sweetest I would seriously consider the golden-crowned kinglet for that honor.

There are two species of kinglets found here during migration: golden-crowned (Regulus strapata) and ruby-crowned (Regulus calendula).  Both are tiny, smaller than chickadees and just a little larger than hummingbirds. Golden-crowned seem to be more hardy, often flocking with chickadees during the colder months, and sometimes being seen here in winter. Ruby-crowneds migrate farther south, and return later in spring.  They are sometimes abundant in May, when warblers are also migrating through.

Right now, golden-crowned kinglets are migrating through, alongside the other early migrant species. They are insect-eaters, and can be found tirelessly flitting among the branches of shrubs and small trees, looking for tiny insects of the early spring, along with spiders and other tiny invertebrates. One can often tell their identity just from their ceaseless movements in the trees. When caught for banding, though, they are active but mostly cooperative in the hand, and it’s then that one can appreciate the colors of these tiny animals. Overall, they are a drab olive-green little bird with a thing line on their wing. On their heads, however, they sport a brilliant yellow-orange mohawk that they can expand or compress depending on their mood. They can quickly go from bland to striking in their appearance.

Often the first indication of their presence is a very simple whistled “dee-dee,” that they call as they forage. It is similar to the single call note of a brown creeper and the ruby-crowned kinglet, although the latter often launches into an elaborate and loud song consisting of a jumble of many notes which is hard to describe. Eventually, both kinglets will continue their migration northward to nest high in the conifers of northern North America. For now though, we are lucky to have them share our yards, and each morning I look forward to hearing the golden-crowned kinglet’s simple song and busy nature as an early gift of spring.

photo- golden-crowned kinglet from US Fish and Wildlife Service

Ripples 3/25/21

Written by Jenna Brandl, Woodland Dunes intern

So tell me, what’s driving you nuts? Could it be the bushy tailed fiend who steals all the bird seed out of your feeders? As a Wisconsinite, I have had my fair share of stories with squirrels. From friends who had these furry creatures as roommates in their walls to up close encounters, I decided to do a little more research into our rambunctious rodents. As it turns out, Wisconsin is home to five different types of squirrel. This includes gray squirrel, fox squirrel, red squirrel, and two types of flying squirrel. 

The gray squirrel, Sciurus carolinensis, can reach about 18 to 21 inches in length and weigh about 16 to 28 ounces. Surprisingly, about 8 to 10 inches of their body length is actually their tail. While most gray squirrels appear to have a grayish coat, it can also vary in shades of black, white, and golden yellow. These squirrels can typically live within any type of habitat ranging from wooded to city. Since they are foragers, they eat wide arrays of plants, nuts, and fruits. Gray squirrels can be a problem, though, when they find access inside a building. So for my friend harbouring squirrels in her wall, you may find insulation and wiring damage.

The fox squirrel, Sciurus niger, is the largest tree squirrel with a length of 20 to 22 inches long and weighs up to 24 to 32  ounces. Their rusty brown undersides which resemble a gray fox’s coat color help explain its name to distinguish it from the gray. The fox squirrel lacks the white tipped hairs like the grey squirrel and has shorter rounded ears. These squirrels typically live in rural areas that are a mix of woods and farms, or are commonly found in southern Wisconsin. Common traits with the gray squirrel include foraging acorns, nuts, or corn, as well as trouble. Although, these squirrels will change their diet to whatever food is available to them.

photo of squirrelThe red squirrel, Tamiasciurus hudsonicus, are generally 11 to 14 inches and weigh 7 to 10 ounces. While its tail takes away 4  to 6 inches of its total length, it can be easily identified by the small size, larger ears, white eye ring, and their reddish coats. An interesting fact about these small creatures is that in summer, a stark black lateral line appears on both sides of its body separating the white and cinnamon colored coats. Winter means the coats colors get richer and ears get more tufted, but the black lines disappear. Red squirrels usually live in the northern two thirds of Wisconsin in the coniferous or mixed woods. Their foraging includes pine seeds, mushrooms/fungi, nuts, fruits, and berries. We have seen a couple here at Woodland Dunes, and have promptly named the most frequent visitor Samson.

The flying squirrels, Glaucomys sabrinus (northern flying squirrel) and Glaucomys volans (southern flying squirrel), are the smallest Wisconsin tree squirrels. The northerns are about 10 to 13 inches and weigh 4 to 8 ounces. They are slightly redder with a grey underbelly tipped in white. The southern is 8 to 10 inches and weighs 2.5 to 3.5 ounces. Instead of a grey belly, they are completely white. While its name suggests “flying,” they can only glide between trees. This is done by a fold of skin along each side of its body that turns into “flaps” helping the gliding process. Turns out they can glide for almost 150 feet and control it’s directions by its flattened shaped tail. Both flying squirrels are also nocturnal animals that live in wooded areas or some suburban areas with mature vegetation. Foraging includes nuts, berries, insects, seeds, and fruit. While they can cause damage inside buildings like their bigger relatives, they usually gather inside communal dens in hollow tree cavities. Aren’t squirrels nuts!

photo credit Pexels

Ripples 3/18/21

 by Jenna Brandt, Woodland Dunes land management intern

It closed in all around us. Sharp thorns, a height of almost six feet, and no way to reach its source without drawing blood. With the help of every intern and several pairs of clippers, we defeated the monstrous bush known as Japanese barberry (Berberis thunbergii). The entirety of this winter season has been a battle in conquering honeysuckle, buckthorn, and barberry within the preserve. While cutting through the honeysuckle and buckthorn with bow saws gave our arms quite a workout, it had nothing on the prickly barberry. 

Japanese barberry is an invasive plant that was introduced to North America in the 1800’s due to its popularity as an ornamental landscaping plant. Some of the characteristics to distinguish this woody shrub are the curving branches with hundreds of sharp spines that are usually about 4 to 10 mm long. They can also reach a height of six feet or taller when left untreated. Not only does this make it difficult to traverse through, but trying to reach its roots to cut and treat rewards you with plenty of scratches. 
During the warmer months, small rounded leaves begin to grow and cluster around the spines, thus hiding their danger. The colors of this shrub can range from maroon, green, or a vibrant orange/red depending on the time of year. These plants also grow small yellow flowers around the month of May and will eventually grow reddish oblong berries throughout the colder months.
 
Unfortunately, these berries are one of the main factors in spreading this aggressive invasive plant. Consumers of these berries, typically birds, will travel great lengths across areas of land facilitating the spread of barberry seeds. By increasing the infestation of Japanese Barberry, it brings many detrimental ecological impacts. The soil being one of them. In previous research, it has been found that barberry changes the chemistry of the soil around it to its preferable conditions for growth. This change in soil pH and other nutrient levels will contribute to that changing of the entire surrounding ecosystem within a given area. Resulting in the disappearance of native plants and animal species.
 
In order to prevent the disappearance and destruction of our native ecosystems, we have to treat the infestation. This can be done with a two step process. Step number one includes mechanical treatment. In other words, hand-pulling, cutting, mowing, or using brush saws as an initial treatment. Step two requires a chemical treatment. By using herbicide applications to the cut stumps of the plant, it should prove effective in deterring any further growth. Resprouts from the previous plant may occur and should be treated similarly. By completing the previous two steps you too can help stop the spread of invasive Barberry!   

This plant is listed by the DNR as restricted, meaning that for most cultivars selling or transporting the plant is prohibited.  There are a few that produce very few seeds, and don’t cause as much problem in the forest.  Please be aware- there are other shrubs that can be planted in your home landscape, including native species.

Although the sharp spines proved to be a vicious enemy, the overall outcome was worth it to protect the natural environment. The battle against barberry was fought, leaving us with the battle scars and tales of our victory.