Thursday, September 24, 2009

River Otters

Nature Watch
By Susan Benson,
CNHM Director of Education

Questions about river otters have been coming into the Museum, as well as observations of them people have shared with Museum staff in local water bodies that. These sleek, muscular animals that I think of as the “teddy bears” of the water are regular residents of our area lakes. Calling a member of the weasel family a teddy bear might not quite be accurate, but every time I see one in the water I am delighted by their facial features and playful water antics.

The aquatic menu that otters select from is quite diverse and large. They will “munch” on small minnows, bass, sunfish, crayfish, frogs, or other aquatic animals. They forage in shallow waters along the banks, and will also eat birds or vegetation. Otters sleep and raise their young in dens such as empty burrows made by other animals, hollow logs, brush piles, or abandoned beaver lodges. Their home range is up to three miles.

During winter it is fun to observe their bounding tracks with their trail dragging between their legs, or their downhill slides towards the frozen lakes or bodies of water. Otters communicate by making sounds, like a bird chirping, a grunting sound when playing or grooming, and a high pitched scream when fighting or mating. When they get surprised or frightened, you may hear them snort.
Otters are known as playful animals. They like to wrestle, chase other otters, and play capture and release with live prey. Each of these "games" helps the otter become better coordinated and helps them fit into the social structure of the group. In the winter, you'll find otters traveling overland by bounding 3-4 times, pushing off with their hind feet, and then sliding 5-15 feet on the snow. Downhill slides are a bonus,

They are excellent swimmers and can stay underwater for up to 4 minutes. They've actually been known to dive to depths of more than 40 feet. Their speed and agility in the water helps them outmaneuver and catch fish and other quick prey. After about a year each otter will strike out on its own and establish its own territory.
All otters must continually groom their fur to maintain its insulating qualities. Otters spend a substantial amount of time grooming, and many species of river otters have designated areas on land for drying and grooming their fur. Most vigorously dry themselves by rolling on the ground or rubbing against logs or vegetation.



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 and exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.

Monday, September 21, 2009

Fall Color Prediction

Nature Watch
By Susan Benson,
CNHM Director of Education


What will the fall colors be like this month and next? I was contacted this week by Midwest Weekends travel guide to predict the fall colors for the Cable area. I felt a little nervous about making such a bold statement. My biggest fear was, “What if I’m wrong?” I decided to go out on a limb (yes, pun intended,) and make my prediction. It then became obvious around the Museum office that it had to be shared with the Nature Watch audience. So, will the colors be good this fall? Here is my prediction…

I predict that we could have a great fall color experience, and this is why. Here are the fall color basics. Three types of pigments are involved in autumn color. The first is chlorophyll, which gives leaves their basic green color. Chlorophyll is necessary for photosynthesis, the chemical reaction in which plants use the energy of sunlight to make sugars. The second pigment group, called carotenoids, produces yellow, orange, and brown colors. The last essential pigment, known as anthocyanin, produces red, purple, and crimson colors.

Both chlorophyll and carotenoids are present in leaves throughout the growing season. Most anthocyanins are produced only in autumn, in response to bright light and excess plant sugars within leaf cells. As the nights grow longer, chlorophyll production slows to a halt. Its green color fades from the leaves; the caroteniods and anthocyanins are then unmasked to show their colors.

The vibrancy of the colors is related to weather conditions that occur before and during the time when the chlorophyll in the leaves is dwindling. The series of warm, sunny days and cool, crisp but not freezing nights we have been experiencing seems to bring about the most spectacular color displays. During these days, a lot of sugars are produced. The cool nights and the gradual closing of veins leading from the leaf prevent these sugars from moving out. Lots of sugar and lots of light spur the production of the brilliant anthocyanin pigments.

The timing of the color change also varies by species. For example, oaks show their colors long after other species have already dropped their leaves. The differences in timing among species seems to be genetic, for a particular species at the same latitude will show the same coloration in high elevations at about the same time as it does in warmer lowlands.

Here is the unknown wild card. The amount of moisture in the soils also affects autumn colors. A late spring, or severe summer drought, which we have had, can delay the onset of fall color by a few weeks. They can also lower the intensity.

Perhaps it is only the optimist in me that thinks that the colors will be great, but regardless, we should all enjoy the experience. This is the best time of year to get outdoors, now that the insects are declining, and the trees colors greet us every where we go. Take a fall color tour. Attend the fall fest activities in many of our local communities. Go for a trek on one of our numerous hiking or biking trails. I hope to see you on the trail!

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 and exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.

Thursday, September 10, 2009

Fall Migration

Nature Watch
By Susan Benson,
CNHM Director of Education

We may still be hoping for summer, but the birds know better. Migration is peaking for many species, especially broad-wing hawks, Canada geese, and some of our nocturnal migrant warblers, flycatchers, vireos, hummingbirds and orioles. Barred owls and whippoorwills have been calling at night. Red-winged blackbirds and starlings are flocking in larger numbers. Keep your eyes out for these migratory treats.

Broad-wings can be seen passing through, with the right winds, in large numbers. Like most raptors, they are reluctant to cross large bodies of water. When they migrate south and encounter Lake Superior, the birds naturally veer southwest along the lakeshore. Broad-wings migrate at high altitudes and seldom stop to hunt during the days of their travels. Because of their dependence on cold-blooded terrestrial prey species, they migrate all the way to Central and even South America. In order to conserve energy on their long journey, they float upward on vertical air currents as high as they can go, and then shoot forward, coasting to the next thermal. These air currents, called thermals or updrafts, often are found above rock outcrops, buildings, or parking lots—surfaces that heat the air above them. When one broad-wing discovers a thermal or updraft, others quickly join it, all swirling upward in a “kettle.” Many different raptors use these same techniques for migration flight. However, these are just some of the fall migration clues at which to search for.

Warblers migrate at night in large flocks. As the full moon wanes after Labor Day weekend, look for bird silhouettes against the moon as they migrate. Anyone with a telescope with twenty to thirty times magnification can often see these birds on clear nights while “moonwatching.” Nocturnal migrants typically are birds that have longer distances to fly. Less wind allows for straight flight, so birds expend less energy correcting or maintaining their course in the air. Cooler nights provide benefits as nocturnal migrants maintain healthy body temperature without large water losses. The night cover also allows the birds to avoid predation. The right conditions can bring about good bird viewing during the next day.

A clear night with a slight, north wind can bring about good warbler viewing the following morning. During the fall, many males bright, spring breeding plumage has faded, but in spite of their paler reflection, they still have distinctive markings that can help with identification. To look for warblers, focus on mature woods, in clearings or edges of thicker forested areas. Wooded lakeshores also attract fall warbler species. Fall migrating warblers move in waves, in groups of mixed species. If a birder hears the “chick-a-dee-dee-dee” of a chickadee, it is a sign that warblers might be nearby, as chickadees often mix in with warbler groups during fall migration. Finally, knowing a little bit about their habitat can aid with identification. A bird foraging at eye-level could be a black-throated blue warbler, or a bird moving up and down a tree like a woodpecker could be a black-and-white warbler. Using these techniques makes it easier to catch a wave of warblers.

Nighthawks can be seen in the evenings in large numbers. These birds can be recognized by their long, thin wings marked with a white crescent near each tip. Adult males can be further identified by their white chin strap and white tail markings. Nighthawks migrate before cold weather settles in so they won't run out of flying insects that fuel their journey south. It’s amazing that these birds never seem to fly into each other as they dart this way and that for their food. They often time their flight with the air travel of flying ants. By mid-September, nighthawks will be gone from our area, and by late October they will be in South America.

Become a phenologist! Mark your calendar each day you see a change in the transition from summer to fall. After many years of recording, you can take pleasure in knowing when to expect an event in nature to happen.

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 and exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.

Thursday, September 3, 2009

Fruits of the Vine

Nature Watch
By Susan Benson,
CNHM Director of Education

With field guides in hand, I stepped onto the dew-laden ground of the Forest Lodge Nature Trail. The sun was shining and the temperature of the late-summer day was warming up nicely. The late summer buzz of the cicadas greeted my ears. It was time to research plants on the trail in preparation of a Fruits of the Vine hike. I was greeted by a heavy-burdened cherry tree, and out the field guides came.

After some moments, I identified, for probably the second or third time (funny how the brain’s retrieval system doesn’t work as well as we age,) this plant as a cherry tree. I observed its alternate, oblong, lance-shaped leaves, and the ripening dark, purple fruit. I took a bite of a ripened berry, and puckered my lips at the bitter, sweet taste. Black cherry is not as highly valued as other cherries because of its taste, but historically has been made as tea made from the inner bark to help cure a variety of health problems. As I was standing near the tree, I noticed the yellow jacket, a wasp that during this time of year is commonly seen around our pop cans or sweet foods as it becomes more eager for food as our summer ends. Several other wasp species also appeared to be sampling the sugar-rich foods.

Chokecherries are another species I identified along the trail. This plant should not be ignored just because it has “choke” in its name. It has a sweeter taste than black cherries, is best harvested when it is ripe, and is eaten mostly as jelly. If you find a chokecherry, be aware that the less ripe fruits with a red tint have an astringent taste. The impact of this astringency causes a dry, puckering feel in your mouth that is caused by tannins. The tannins change the structure of our salivary proteins, causing a sandpaper feeling in our mouths. Astringency tastes unpleasant to many mammals, but birds do not have a “sense of astringency” and so eagerly eat these fruit. Raccoons, chipmunks and deer mice feast either on the fruit, or extract the round seed pit inside. Black bears will often pull chokecherry branches to the ground to strip the cherries right off the plants, damaging the tree in the process. This wild fruit makes a tasty juice, jam, jelly, or syrup for humans.

Other tasty treats to look for right now while out on the Trail or near your house include juneberries, raspberries or blackberries. Try eating American or beaked hazelnuts, or experience a milkweed pod that is about two-thirds grown, known to have a nice vegetable flavor. Be aware, though, that you are competing with squirrels, foxes, deer, ruffed grouse, turkey, woodpeckers, mice, insects, and deer for those delectable wild foods!

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 and exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.

Tuesday, September 1, 2009

Turkeys

Nature Watch
By Susan Benson,
CNHM Director of Education

The day I saw my first badger was a highlight in my naturalist life, but was exciting for another reason. That same evening, I observed a turkey and four of its young crossing the road in front of me. Wild turkeys have been living in the vicinity of my house for a few years now and almost every summer I get the pleasure of seeing their large families. I continue to monitor in my phenology observation journal any observations, and I am keeping track of their success in this small northwest corner of the state. Successful restoration of wild turkeys has happened in Wisconsin, and it is surprising to see how well they seem to be doing in our region.

The turkeys around my house have plenty of food sources available to them. Bordering an active farm means the turkeys have access to corn and plant remains in cow manure. They can seek out unharvested crops, alfalfa, or grain waste. They also have access to native cherries, blackberries, raspberries, red elderberry, acorns, and seeds from the area’s maple, pine, spruce, balsam fir, and beech. Turkeys can also choose to eat catkins, buds, and leaves from the birch, hazelnut, ferns, strawberries, wintergreen, partridgeberry, clubmosses, trailing arbutus, bunchberry, and other ground-layer plants and grasses. There are plenty of grasshoppers, earthworms, grubs, leafhoppers, beetles, or crickets on which they can feed. These food sources meet the needs of what most Wisconsin turkeys seem to do well with: a fifty-fifty mix of oak woodland and agriculture. This is just part of their habitat, however.

Turkeys roost in trees overnight as protection from predators. Areas with dense cover keep them from wind or inclement weather. Trees with trunks about a minimum of twelve inches in diameter with horizontal branches are best, and in winter, turkeys will roost in conifers to better insulate them from cold weather. Denser understory vegetation provides safer nesting cover during the breeding season. Areas with insects or other protein sources are preferred breeding areas as turkey young eat one-fifth of their body weight each day. The home range of turkeys can vary from 135 to 500 acres depending on the time of year and availability of food and cover. Although turkeys are very adaptable, research suggests that they do better when food, roosting sites, and nesting sites are located close together.

Why do turkeys seem to be doing so well in northwestern Wisconsin? When outdoor temperatures go below 50 degrees Fahrenheit, a turkey’s metabolic rate speeds up, allowing them to survive colder temperatures only if they have enough food. Snow with a depth of more than twelve inches also hampers their walking ability and opportunities to find food. The northwestern part of our state has an average of forty to fifty days of twelve or more inches of snow, usually limiting turkey survival rates. Our recent warm winters must be contributing to their success.

Historically, turkeys were not documented except in the very southern parts of the state. In the 1970’s, turkeys were brought from Missouri to several sites throughout the southern part of the state, with more limited releases north of the ten-inch snow line. It is believed that the populations in this area are probably “immigrants” as those northern populations survived many of our warmer winters and dispersed into our area.

It is exciting to see the male turkeys showing their beautiful strut in the spring, or to see the young trailing behind their parent. I continue the search around my house for turkeys – their feathers, tracks, or observations I occasionally enjoy, and my next goal is to hear them gobble! If you have your own turkey story to share, please Email the Museum at info@cablemuseum.org.

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 and exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.

Bird Flight

Nature Watch
By Susan Benson,
CNHM Director of Education

The robins are back again. For the past two days, large numbers have been weighing down the trees in the Museum’s outdoor classroom. Robins flock together for feeding and for migration, so I imagine they are getting ready to instead of “raid the frig” they are ready to “raid” the mountain ash berries. Watching them flutter and fly is such an enjoyment. Have you ever wished you could be a bird for just one day, just to feel what it is like to fly? Bird flight is an amazing adaptation!

The wing of a bird consists of two functional parts: an inner part nearest the body and the outer hand. The outer hand, with its pliable flight feathers, functions as a propeller. The inner part provides the bird almost exclusively with lift.

All birds, except the hummingbird, move their wings at the shoulder, elbow and wrist. The entire hummingbird wing is a “hand wing,” or propeller. It does not soar or glide. Since the hummingbird moves its wings solely from the shoulders, it has great maneuverability in the air. The wing is extended throughout the whole stroke, making a figure eight and producing lift on both the up- and down-stroke. With this beat many hummingbirds can beat their wings fifty-two times a second.
Gliding is the simplest form of flight, when a bird’s wings make no propulsive movements. It is actually coasting “downhill” in reaction to air currents. Larger birds such as the albatross, condor, vulture, eagles and storks minimize their use of energy while gliding.
A soaring bird is one that maintains or even increases its altitude without flapping its wings. There are three main requirements to soar successfully: large size, light wing-loading, and maneuverability. Many birds that use soaring as a flight technique have deep slots in their wings to decrease drag and aid their take-offs.

Birds may stay aloft by riding rising warm air current called thermals, or by obstruction currents, which are updrafts of air caused when steady winds strike and rise over objects such as mountains, hills, buildings, and sand dunes.

Many birds hover by flapping their wings sufficiently to hold their position over one point on the ground. A hawk or kestrel does this by beating its wings, depressing and spreading its tail feathers, and holding its body at a nearly vertical position. They can hover for longer lengths of time by flying into a headwind, allowing them to stay stationary.

Much of our human flight was created through the intense observation of birds in flight. We learned from their streamlined bodies that help them overcome air-resistance. We discovered their hollow bird skeleton used to reduce weight, and the large keel of their breastbone. Most of all, they give us much entertainment and enjoyment.
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 and exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.