Nature Blog

Ripples 1/14/2021


Written by Kennedy Zittel, Land Management Intern

As the other interns and I walked along Cattail Trail enjoying the sunny winter day, Jenna stopped along the boardwalk and pointed out that the cattails were moving! To our surprise, we saw a weasel! Perfectly blending into the snow besides the little black-tipped tail, this small creature was dragging a large bird across the ice right next to the boardwalk that we stood on. Given how well this animal blended into the snow, it was no wonder how the bird that it caught didn’t see it in time. When we got back to the nature center we began to research to try and figure out what type of weasel it was that we saw. 

The three main types of weasels within North America are long-tailed weasels (Mustela frenata), short-tailed weasel (Mustela erminea), and the least weasel (Mustela nivalis). These three weasels vary in size with the long-tailed weasel being the largest, then the short-tailed weasel, and the least weasel is the smallest. Long-tailed weasels are around 13-18 inches long with a 4-6 inch black-tipped tail. Short-tailed weasels are around 12 inches long with a 2-4 inch black-tipped tail. Least weasels are only about 6 inches long with a short tail that lacks a black-tip. The least weasel is also the smallest carnivore (of the order Carnivora) in the world! 

After we learned more about the sizing and coloration of the three weasels, we decided that we saw a short-tailed weasel, also known as an ermine. This was based on how it had a black-tipped tail (ruling out the least weasel) and how it had a tail length and body size that was more comparable to the short-tailed weasel. 

Weasels (mammals of the genus Mustela) include least weasels, short-tailed weasels, long-tailed weasels, polecats, stoats, mink, and ferrets. The family that weasels belong to, Mustelidae, includes badgers, wolverines, and otters too. Weasels are small predators that have long slender bodies with relatively short legs. The slenderness of their bodies enables them to follow prey into small burrows. Mice and voles make up a majority of the weasels diet (around 60-80%). Weasels will also eat frogs, birds, and rats. Within the warmer months, all three weasels have dark brown fur with a creamy white colored stomach. During the colder months all three weasels fur may turn white to help them better camouflage with the snow. Weasels are also crepuscular, meaning that they are active at twilight (dawn and dusk) which explains why we saw one early in the morning. 

Cattail trail has brought us so many different wildlife sightings, regardless of the time of year. We have seen muskrats coasting through the marsh, mink scampering along the boardwalk, bald eagles soaring in the sky above, a weasel sliding across the ice, and so much more. The sighting of the weasel was a good reminder to us all that when you go out into nature, just take your time and really look around you so that you see all of the wonderful things that surround you. If Jenna wouldn’t have stopped on the boardwalk to gaze out at the marsh none of us would have seen the tiny predator dragging his meal across the ice. Seeing such a tiny creature with such a large meal slipping across the ice brought us all great joy, and it will be a story that we all tell for a long time.

photo- short-tailed weasel from Wisconsin DNR  

Ripples 1/7/21

Here along Lake Michigan, it seems that every season has its own unique qualities in terms of weather.  No two years seem to be the same, and within each season there are often significantly contrasting periods.  As we all know, wind direction alone can cause marked changes in temperatures, but there are larger and broader factors that come into play.

Its safe to say that the first half of our winter has been mild.  Even though it still feels cold, we have not been as cold as our  average temperatures typically reflect.  The National Weather Service collects and analyzes data for certain locations, and they indicate that this winter has been significantly mild- the December average temperature was 6.6 degrees above normal, and so far for January it has been about 3 degrees warmer on average.  Again, it may not seem noticeable to us, but it can have a profound effect on wildlife.

For example, the soil was still not frozen until Christmas Eve – on December 23 not only was the ground still thawed, but an earthworm was seen on the sidewalk at the nature center.  A few sandhill cranes, which typically withdraw from our area about December 1st, are still being seen nearby.  Some diving ducks, which migrate through in November, have still been recently seen along the lakefront.  And just a few days ago we received a call from a neighbor who observed a garter snake sunning itself on the top of the snow.  The rare bird sightings list from Cornell Universities’ eBird database, has many unusual southern birds lingering around- a Baltimore oriole is being seen near Wausau, a number of warblers and other migrants are being found in locations across the State.  This makes for an interesting season for nature spotters, enhanced by the more comfortable temperatures we are experiencing.  

In the face of our lingering Covid-19 situation, we are benefitting from the more pleasant temperatures.  At Woodland Dunes, our intrepid squad of interns have spent their winter college break slaying invasive shrubbery in the preserve – something that would not be possible in normal January temperatures.  There can, however, be a downside to a mild winter.

The cold season helps to keep certain populations in check, acting as a sort of disinfecting agent.  There are a lot of unwanted and invasive species to our south, and our cold winters help keep them in check.  Without severe cold, the emerald ash borer is more likely to survive and kill even more ash trees next year.  Japanese beetles and the brown-marmorated stink bug are also able to survive, along with the Asian multicolored lady beetles which already winter in my old farmhouse, as well as the aphids they feed on.  Some insects also carry plant diseases with them, and if the insects survive in greater numbers there is an increased risk of disease transmittal in spring.  

Sooner or later, I’m sure we’ll have a harsher taste of winter.  But while that may be uncomfortable to us humans, it is not necessarily a bad thing.  As in other aspects of our lives right now, we should appreciate what is “normal” for the good that it can provide us.

photo- a lowly earthworm, one of the first signs of spring- in December!  

Ripples 12/28/20

Written by Jessica Johnsrud, Education Coordinator

Every winter, I look forward to snowshoeing, sledding and hearing the crunch of the snow under my feet. There’s something photo of otter tracksmagical about walking in the snow at night or cruising down a hill in a sled that makes me feel like a kid again. Humans aren’t the only creatures that play in the snow, and I was recently reminded of this when I saw river otter sign at the end of the Cattail Trail.

River otters are native to Wisconsin and live in rivers, streams and larger lakes. They belong to the mustelid family, a group of carnivorous mammals that includes weasels, badgers, fishers and others. River otters spend much of their time in the water and have long, cylindrical bodies, dense fur and webbed feet. On average they weigh between 15-19 pounds and are 3-4 feet in length. They are easy to identify by their long, thick tail which is tapered at the tip. The tail is very muscular and helps the otter dive to depths of 36 feet or more and swim up to 8 miles per hour. They dine on suckers, catfish, small mammals, snakes, crayfish, frogs and insects.

River otters have an interesting reproductive strategy. They mate in March and April, shortly after the female births her annual litter, but the females are able to put their pregnancy on hold. This is called delayed implantation or embryonic diapause and means the eggs are fertilized, but do not implant in the uterine wall for up to one year! The female doesn’t actually have control over this, it’s a physiological response to environmental cues. Waiting until her current young are weaned and conditions are prime, gives the female and her future litter the best chance of surviving. About 100 other animals experience delayed implantation including beavers, bears and armadillos.

Before giving birth, the female prepares a den in the bank of a stream or uses an old beaver lodge or muskrat home. In March or April, she gives birth to two to five helpless, blind pups. They grow quickly and emerge from the den when they are about 2 months old. The female teaches her young to swim by carrying, dragging or enticing them with food. They stay together as a family through the first winter, then the young disperse and find their own territories.

As I eluded to before, otters are known as playful animals and learn through play. It’s an important component of an otter’s life and is a way of strengthening social bonds, improving hunting skills and scent marking territories. They wrestle, chase and play capture and release with live prey. They have even been observed swimming in circles to create a whirlpool, which pulls up fish from the bottom of the river. Otters spend a large portion of each day scent marking territory by urinating, defecating, scratching and rubbing their scent glands on rocks and trees. They also roll around and flatten plants in specific areas and to leave their musky odor behind. Otters also seem to enjoy playing in mud or snow, quickly bounding, then sliding on their bellies. You can look for otter tracks and belly slides on the ice and snow on area rivers.

I think humans could take a lesson from river otters and focus more on play. Maybe this could be a fun and refreshing New Year’s resolution? Sledding anyone? 

Attached photos: otter tracks and otter belly slide and tracks on West Twin River

Ripples 12/24/20

photo of Fox Sparrow

Fox sparrow

Here we are, at the darkest time of year.  It’s no wonder that just like native people, we add light wherever we can, illuminating our homes with electric displays in place of the bonfires of long ago.  Since June we have watched our days grow shorter and cloudier, unless we are slapped with a cold front to send temperatures tumbling but bring in clear, dry air.  Once again, the wild things, oblivious to human pathogens, go about their business under relatively good conditions: little snow and only moderate cold. Birds don’t really need to visit our feeders like they do when snow covers their wild food, causing people to wonder if they are alright if unseen. I don’t know if birds feel gratitude for such weather- I rather doubt it.  They seem to continue regardless of conditions, perhaps lingering a bit farther north for the time being.

A sense of gratitude seems to be important to the well-being of people, however.  We have the ability to discern when things are going well, or at least that they could be worse than they are.  We are challenged these days by inordinate health concerns, political discord, and a general sense of frustration that things are not as we wish them to be. This year has seen people taking out their frustrations on each other more than I can remember, and I’m getting to the point where I can remember a lot of years.  It seems easy; though, to remember the times when I really felt grateful, and those times seem to center on one of two things – family and nature.

I think we are biologically programmed to feel gratitude for our families, our elders and our children.  That is, if we have been fortunate to have grown up with a sense of being loved and cared for.  Unfortunately, too many of us have not experienced enough of that.  Nature, however, is all around us and should be accessible no matter our circumstances.  In my own life, I have experienced that sense of gratitude for the life around me even during the most trying times.  If a day is full of frustrations, even a few minutes in a natural place can make me feel better.  There is almost always something interesting to be encountered and wondered about just a few feet from my door.  Perhaps it’s denial, but in a green place I can easily forget problems if I am aware of the moment, and what is happening around me.  No wonder the first people of this area referred to Grandmother Earth.  Who better to embrace, comfort, and care for you.

So if gratitude is so important, what am I most grateful for this year?  People who care for each other, and for the Earth, first off. I have been so fortunate to meet, work, and live with such folks.  And nature, and what it gives us.  Right now I’m grateful for the fox sparrow which lives under the juniper bush by the bird feeders – brightly cinnamon colored, darting out to grab a seed or two and do its little scratching dance.  Or the flock of cedar waxwings, delicately shaded in their colors, who descend on that same shrub to glean berries from the branches.  Or the pileated woodpecker which lives across the river, or the bald eagle cruising the shore.  Or the chickadee that bites me fiercely as I try to put a band on its leg.  And the fact that the internet lets us at least see and talk to our family at Christmas.

Next year will be better, for people and I hope for nature.  I also hope that a sense of gratitude will replace the frustration we all feel now, and that it brings us to care more for the natural world and each other.  And see things as they truly are. 

Ripples 12/17/20

by Jessica Johnsrud, Education Coordinator

It was a cold and windy day and I was walking outdoors with a friend and her young children. The little ones came upon a small pond that was mostly iced over and immediately tried to break the ice with their feet. As I watched, they stomped through the ice, getting their feet and gloves wet. They continued to play contently, with sopping wet gloves. I affectionately call these two “turkeys”, but as I watched them unphased by the cold and wet, I realized I should probably start calling them “beavers.”
 
The American beaver is born for aquatic conditions and has several adaptations for living in the water even in the winter. First, it has a built-in wetsuit consisting of two layers of fur. There’s a shorter, thick underfur which traps warm air against the skin. This is protected by a longer layer of fur called guard fur, which keeps water away from the layer underneath. Beaver fur is also waterproof because of oil produced in castor glands located near the base of the tail. The beaver routinely combs this oil in its fur using a specialized split toenail, called a grooming claw.
 
When swimming underwater, beavers close valves in their ears and nostrils to keep water out. They also have special lips that seal the mouth but leave the front incisors exposed, allowing the animal to carry branches while swimming. They have a clear eyelid called a nictitating membrane that covers the eyes like goggles, so they can see while swimming. Their hind feet are webbed, which helps them swim. These nifty features come in handy as beavers spend a lot of time in the water and can remain underwater for 15 minutes at a time.
 
Beavers are often referred to as “nature’s engineers” because they use their large incisors to cut down trees and build a home (lodge) and construct dams in rivers. Why all this busy work? Beavers prefer to swim in slow or stagnant water because it’s less expensive energetically. Damming up moving water and creating a pond, also gives them better access to food. They feed on soft bark and inner bark of trees as well as aquatic plants and fleshy roots. 
 
It’s pretty amazing that beavers are able to eat and acquire energy from such meals. They have a specialized digestive system that allows them to break down and extract nutrients from the wood. Beavers have an enlarged cecum, the pouchlike structure which is part of the large intestine that acts as a fermentation chamber. It contains bacteria and fungi that help digest the cellulose from the bark. Beavers also practice coprophagy, meaning they eat their feces and digest it a second time, thus obtaining as much nutrients as possible. Other animals also practice this, including cottontail rabbits, mice and other animals.
 
Not only do beavers have interesting adaptations, they are also considered a keystone species because they play a critical role in the biodiversity of an ecosystem. Many species depend on beaver-created habitat and the removal of beavers would drastically change that ecosystem. Habitat created by beavers helps recharge drinking water aquifers, removes pollutants from surface water and ground water and produces food for fish and other animals. This makes coexisting with beavers an important part in protecting the wetlands and habitats of which we are a part.