Wednesday, February 27, 2008

Frogs & Snakes in Winter

Nature Watch
February 27, 2008
By Susan Benson,CNHM Director of Education

So you think you get cold in the winter? Consider the wood frog. This little amphibian actually freezes solid during the winter months. While frozen, these frogs have no heartbeat. They do not breathe. Their blood does not circulate. Their nerves barely register electrical impulses. Yet their vital organs are not damaged, even after being frozen solid for weeks on end. Come spring, the little frogs simply thaw out and hop away to woodland ponds to mate and carry on with life. Spring peepers, gray tree frogs and upland chorus frogs also may freeze and thaw several times during the course of a winter. How do they do it? The answer is antifreeze. When ice begins to form on a wood frog’s skin, the frog’s liver releases a high level of blood sugar, enough to fill the blood vessels in all vital organs. The blood of frozen wood frogs may have a glucose level 100 times as concentrated as that in average human blood.
This highly concentrated sugar solution resists freezing, and although nearly two thirds of the frog’s body water may turn to solid ice, that ice is located in non-vital areas such as the bladder, stomach cavity, beneath the skin, between organs and muscle fibers and between cells. Ice does not form within the living cells and therefore does not damage organs. Come spring, the sugar is quickly removed from the frog’s blood by the liver, and the frog returns to what we’d call “normal.” Frogs are not the only animals that survive the winter as living ice cubes.

Garter snakes, normally the last snake species to hibernate in autumn and the first to emerge in spring, can tolerate a night or two of being frozen if they’re caught away from their hibernation hideaway. Adult box turtles can survive freezing and newly hatched painted turtles freeze solid and thaw out repeatedly when in their nests during their first winter. Not all animal adaptation to winter is so extreme. Many birds that spend winters up north grow a winter coat of heavy-duty feathers to help insulate them from the cold. Goldfinch feather weight is about 50 percent higher in winter than summer. Even with feathers fluffed, however, most birds need to generate extra heat to survive, and they do this just as humans do: by shivering. Chickadees, for example, shiver more or less continuously throughout winter except when they’re flying. This winter, when you may be feeling chilly and tempted to exclaim “I’m freezing!” remember that there are animals out there that actually are freezing!

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at to learn more about exhibits and programs.

Wednesday, February 20, 2008

Birkie Snow

Nature Watch
February 20, 2008
By Susan Benson,CNHM Director of Education

It’s happening again this year. I feel my body heat rising, and the insane desire to flop my arms and legs back and forth in an incessant beat. It’s a feeling we are all familiar with – Birkie Fever!

We all know that snowflakes are a collection of snow crystals, often with the six-sided hexagonal shapes, sometimes bound together into a puff-ball (these flakes can consist of up to 100 snow crystals clumped together.) The prisms that are formed are due to the molecular structure of water. This winter has also brought us rime, which is super cooled tiny drops of water that quickly freeze into whatever they hit, and also often occur in a fog. We’ve also seen graupel, a loose collection of frozen water droplets that are sometimes called soft hail. Just what does snow mean to the over 6,100 skiers that are skiing a race this weekend as part of the American Birkiebeiner?

Powder is freshly fallen, untouched snow that forms a smooth surface while giving you a feeling of floating in outer space. To a cross-country skier, powder is often packed in thick layers forming a natural pillow for any crashes (I’ve experienced this many times,) but ungroomed, fresh powder is beautiful but sloooow.

Slush, or slop, as it’s known in the skier world happens when the air temperature is warmer than the freezing point, so the snow begins to melt and its water content is very high. These delicate snow crystals change into large grains of ice, and slop is formed. To a Birkie skier, this means slow, difficult skiing with wet socks. Standing water on Lake Hayward can sometimes occur during these conditions, but all parts of the race can be difficult in slop, and people can become dehydrated. 1996 was a slop Birkie.

Frozen granular snow is defined as a hard surface of old snow formed by granules freezing together after rain or warm temperatures. For the Birkie, they have great machinery to help make the granules of snow very fast, and most racers really like this, as long as its groomed well.

Machine tilled snow is loose granular snow repeatedly groomed by power tillers so the texture is halfway between powder and granular, pulverized so that the crystals are like powder sugar. This snow makes the best all-around condition for the race - fast, safe, and durable.

Windblown snow is powder or granular snow that has been blown by the wind and has formed a base. A few exposed areas on Lake Hayward or Duffy’s Field on the Birkie trail can have windblown snow, and it can slow skiing in those areas as the crystals are sharp and abrasive.

I wrote this article with the help of local skier and friend Chris Young. Here is what he had to say about snow during the Birkiebeiner race:

“Snow is good, at least for us in Birkie country. Ideally, though, we like the snow to come down in manageable amounts, 2-3 inches at a time so that groomers can deal with it adequately. This is important for Birkie because it makes for a better course. We want the snow to fall at temperatures of 25-30 degrees so that it is slightly moist. The moisture in the snow allows the groomers to adequately pack the snow, making a very firm, dense base. This makes for very durable snow conditions that you need when you have 6,000 skiers. The big groomer has a tiller, and it tosses the snow, like you till soil - grabbing the snow, spinning it, and packing it down, getting the air out of it. If it’s really cold, it’s very dry and abrasive and tends to keep the air in the snow pack, making for slow, soft conditions.
Birkie trouble begins when the snow is too warm, and the moisture and the soft, collapsible nature of snow makes for difficult ski conditions. That creates suction between the skis and the snow. This has a dramatic effect on slowing the skis. If conditions are in the teens or 20’s this is ideal because snow becomes durable and is at its fastest. This makes for a pretty happy bunch of racers. Temperatures in the teens and below zero bring new problems. Not only is it cold and hard to dress for, the moisture in the snow freezes, creating very sharp, abrasive snow crystals, slowing skiers down. Ask any Birkie veteran about severe cold weather and they will talk about the dreaded sandpaper conditions.”

According to Chris, this year is an ideal year for the Birkie, as we had snow, followed by warming, and then had enough fresh snow to mix in with the granular thawed snow to make for a nice race course - the trail is absolutely immaculate. Whether or not we are a skier, we continually deal with the conditions listed above, and can appreciate what skiers experience. Get out and enjoy the winter weather and snow, and keep track of the changes in the snow conditions – now you know what to call that slippery stuff that creates so much fun!

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at to learn more about exhibits and programs.

Friday, February 8, 2008

Nature of the Land

Nature Watch
February 8, 2008

By Susan Benson
Director of Education
Cable Natural History Museum

It is finally snowing again, and I am reminded of something I once read that listed 10 Ojibwe words for types of snow. As I recall, the writer was basing his information on Frederic Baraga’s Dictionary of the Ojibway Language. Referring to my own copy of A Concise Dictionary of Minnesota Ojibwe by John Nichols and Earl Nyholm, I find at least seven different variations. Snow in Ojibwemowin (the Ojibwe language) is goon, but crusty snow, or snow with a crust on it is onaabanad. Deep snow is ishpaagonagaamagad, and zhakipon means “there is a heavy wet snow falling.”

Naming things, at least in some native languages, seems to be a practice of describing something in one word. Not just naming it, but in some cases actually describing a thing in a particular moment and giving that thing in that moment a name. Native languages like Ojibwemowin also name things in a way that alludes to if not directly states the importance of something to the people. Ininaatig is the Ojibwe word for the maple tree, but the name translates more closely to “our tree.” Why is it “our tree”? Because that sap that is gathered from ininaatig each spring is an important source of food for the Ojibwe people (and for many non-native people as well!). The Ojibwe name for the maple tree alludes to a story; it is more than just an arbitrary name.

Another good example of the richness of Ojibwemowin is in place names. Many Wisconsin towns and water bodies have Ojibwemowin names. Here in our area, a good example is Lake Namekagon, or Namekaagong-zaaga’igan. The last part of the Ojibwe name, zaaga’igan, is the word for “lake.” The Ojibwe name Namekaagong, and the modern derivation “Namekagon,” mean “lake at the place of many sturgeon,” or “many sturgeons lake.” The root word of this name is Name, or sturgeon, an important species to the Ojibwe because Name is considered the “king of fish” and is the Chief of the Fish Clans. The cultural importance of sturgeon alludes to the importance of Lake Namekagon.

I am fascinated by Ojibwemowin, but I am in no way fluent. I know a few words, but I do not know the language. I would like to. If French is the native tongue of those living in France, Italian is what is spoken in Italy, and a mixture of tribal languages creates the cultures of Africa, then I think the native tongue of the United States, perhaps all of North America, is the various languages of the first people, the Anishinaabe. In northern Wisconsin, that is primarily Ojibwemowin. It is the language of this land. Unfortunately, the use of all native languages is declining in favor of the more cosmopolitan English. As a result, fewer young people are learning the language and there are increasingly fewer elders who are left to teach it. But this is changing. In parts of our area, Ojibwemowin is becoming a part of school curricula, and an ambitious grant-funded project at the University of Minnesota-Duluth called “Ojibwe Movies” ( is helping teach the Ojibwe language by embedding movies in a language learning software that will be available through a web site and/or on a DVD.

I mentioned two books above that are first steps towards learning, but there are a growing number of other sources. The Great Lakes Indian Fish and Wildlife Commission has compiled an Anishinaabe atlas of the ceded territories in northern Minnesota, Wisconsin, and Michigan. Gidakiiminaan (“Our Earth”) is available in both print form and as a CD. A companion CD, Indinawemaaganidog, is an interactive dictionary/field guide to plants and animals in the ceded territories, giving the Ojibwe names for select species along with additional information such as recordings of individual bird songs. A third CD, Onjiakiing (“From the Earth!”) is a source of information about plants, fruits, and plant materials used by the Ojibwe. All are available through the GLIFWC website (

Another outstanding resource is the language section of the “Lac du Flambeau News” as well as their website; click on “Language.” There are also Ojibwe language classes taught at the Lac du Flambeau, LCO Community College, Northland College, and at the University of Minnesota in Duluth.

Even if you are not Native American, knowing something about the native language of our shared place is important. It gives the land a richer context and makes us more knowledgeable about it and about our place in it. After all, gakina awiiya (“we are all related”).

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at to learn more about exhibits and programs.

Friday, February 1, 2008


Nature Watch
February 1, 2008

By Sue Benson,
CNHM Director of Education

Though February is technically the heart of winter, you’ll notice that the days are getting longer. At the beginning of February we have 10 hours of daylight, and by February’s end we’ll be up to 11 hours of daylight.

February is a challenging month for most over-wintering animals. Woody shrubs and woody vegetation don’t supply the nutrition for animals that summer greens can. In fact, the high cellulose content in woody shrubs means that the animals will need more time and precious energy to digest the material. Energy is so valuable during this time of the year that many animals, including deer and squirrels, will reduce their movement drastically just to conserve energy. February and March are months that you may think twice about shooing the squirrels away from your bird feeders because they may need the wood as much as the birds.

Keep your eyes out for signs of deer. Primarily browsing animals, they will eat acorns, fungi and grass. They also browse on twigs of basswood, ironwood, sugar maple, staghorn sumac, and other trees and shrubs, eating mostly pencil-sized woody parts. This diet creates a deer population that needs to eat almost continuously in order to get enough nutrients to remain strong and healthy. Biologists have found that a healthy deer can eat 10-to-12 pounds of browse every day. A deer could survive on 2-to-3 pounds per day; 6-to-8 pounds are needed continuously. However, white-tailed deer will also catch and eat fish in shallow streams, eat small birds, and dig through snow to feed on wintering colonies of ladybug beetles. Unlike most mammals, deer do not have front teeth on their upper jaw. It can be easy then to differentiate when looking for deer browse. A tough chewed twig is common as deer browse, while other "twig eaters" like snowshoe hares and rabbits create a sharp-edged cut.

Many of Wisconsin's larger animals, especially large birds and carnivores, begin their breeding seasons during this time of year. Female wolves, foxes and coyotes will become impregnated and expect to give birth in late April or May. Female black bears are quite lucky as their cubs are born while "mom" is either sleeping sound or rather hazy from a few months of uninterrupted sleep. After being born the cubs will snuggle in close to mom's armpits near where her teats are located, a characteristic unlike most mammals. Also during this time, crows, ravens, barred owls and great horned owls will start their courtship to attract a mate. The courtship of crows and ravens consists of aerial acrobatics to impress a mate. This can be easy to observe as the birds will twirl, twist, nose-dive and do all other sorts of "stunts." Male owls, on the other hand, will call and hoot until a mate is found. Afterwards they will steal the nest that another animal has created, such as a squirrel den or broad-wing hawk nest.

As the days get longer, the internal clocks of many bird species will trigger them to begin their migration north. Some of the early arrivals may begin to show up during February, like juncos, gulls and maybe even an early robin. In no time at all, waterfowl, blackbird and grackles will be showing up.

One of the most active yet rarely seen mammals during the wintertime is the beaver.
As most ponds and lakes are frozen the beaver will remain very active underneath the ice.
During the fall, beaver’s will drag branches of their favorite trees into the water near their lodge. They then can sneak out of their lodges through an underwater entrance to each food cache. A beaver’s lodge is built so well that even on the coldest days their lodge can remain at a temperature well above 40 degrees.

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at to learn more about exhibits and programs.