Tuesday, June 26, 2012

Loon Language

The mournful wail of a common loon echoes across the glassy water. From a neighboring lake, another loon replies with the same smooth cry. The loons are keeping track of one another, maybe as neighbors, maybe as mates, maybe as rivals.

Sometimes the still night air is pierced by the maniacal laughing yodels of two male loons. This signifies a battle over territory. Home territory means a lot to loons. The longer a male resides in the same territory, the greater his chance of raising chicks to adulthood. The resident male will fight to the death if necessary to defend his island, lake or bay. Even if the invading male wins, the resident female will stay on the territory with the new male.

An invading loon, looking for his own place to raise a family, will fly over an occupied territory and first give the wavering tremolo flight call. If the resident male is willing to fight for the prime real estate, he will reply with a yodel. The invading loon can tell by the lowest note in the tremolo approximately how big the defender is, and use this information to decide whether a fight is in his favor or not. If he chooses to fight, the invader replies with his own unique yodel. Loons can tell each other apart by their calls, and even third-graders can tell loons apart by looking at sonograms of their yodels!

The male chooses a nest site hidden in tall vegetation near the water. The female builds the nest by pulling plants around her body to form a low bowl. After that, they share the parenting duties 50/50. Alternating incubating and eating, they wait for 26-31 days until the two eggs hatch a day apart. The parents communicate with the chicks using a soft, short “hoot.” If eagles are present, the parents may give a version of the tremolo flight call. Bald eagles are a known predator of loons, and the alarm call tells the chicks to “DIVE NOW!”

Eagles are not the only danger for loon chicks. Gulls are also nest raiders. In the Boundary Waters Canoe Area, fish guts left by anglers allowed the population of gulls to increase. More gulls meant fewer loons – and now the Minnesota DNR and others encourage anglers to dispose of fish remains in the woods, away from aerial scavengers.

Many anglers enjoy watching loons on their favorite lakes, while others may see the loons as competition. Loons mostly eat smaller fish like yellow perch, and do not have a significant impact on game fish. Humans can negatively affect loons in several ways, though. Excessive wakes near nesting sites can knock eggs in to the water. Snagged fishhooks and line can entangle many kinds of wildlife. Lead sinkers are also a major issue.

Loons do not have teeth, and neither do they have a mechanism like owls to cough up pellets of undigested hard parts. The fish bones and fish scales have to go all the way through their digestive system. To achieve that, loons have incredibly strong gizzards, and they ingest small, round rocks to help pulverize their food. Unfortunately, lead sinkers look like good gizzard stones. Many loons and other wildlife die a prolonged and painful death by lead poisoning every year.

Lead is not the only toxin we introduce into lakes. Every year around the Fourth of July, and sometimes throughout the summer, we sprinkle a wide assortment of toxic elements into the lakes. We are usually so awed by the spectacle of the beautiful fireworks reflecting on the water that we do not think about the morning after. The noise of the explosion itself can frighten loons of their nests – leaving the eggs open to predators. The plastic casings of the fireworks can sneak into the food chain, causing malnutrition problems. Plus, those interesting, but sometimes carcinogenic elements in the fireworks – the ones that make the cool colors when they burn – can end up in the lake.

This time of year we can see days-old chicks so fluffy they pop up like corks, and awkward teenage chicks just learning to dive. Some loons are still incubating eggs – trying to nest for a second or third time after their first attempts were foiled by thunderstorms, raccoon raids, or other bad luck. Please try not to make their tough parenting job any harder!

You can see adult and baby loons and learn more about their amazing features every Thursday morning from July through September on the Loon Pontoon tours I host on Lake Namakagon. Last summer we watched two chicks grow up week by week until they migrated south for the winter!

Loons are icons of our beloved Northwoods. Their sight and songs bring joy to many residents and visitors of the area. As you enjoy their home, please consider how your behavior can affect them. Thanks!

Friday, June 15, 2012

The Next Generation

The ice cube trays filled up quickly as six boys in swim trunks and ball caps scoured a rocky riffle in the Namekagon River. Using forceps, these Drummond Middle School students carefully placed one small, leggy, wiggling critter per section in the trays.  No doubling up – the critters might eat each other and destroy good data in the process.

John Kudlas, member of the Barnes/Eau Claire Lakes Association and designer of the Eco Education program, instructed the students in the proper techniques for collecting critters without harming them or their habitat. He also stressed the purpose of this stream study: benthic macro invertebrates (things without backbones that live on the bottoms of streams and are visible to the naked eye) spend at least half their life in the water, and they are excellent indicators of ecosystem health.

The Namekagon River is in excellent health, according to the invertebrates. Its clean water, abundant wildlife, beautiful scenery, and diversity of plants make it the perfect place for an adventure. After filling out their data sheets and gently releasing the ice-cube-tray occupants back into their home, the boys loaded five canoes borrowed from the Friends of the St. Croix Headwaters’ “Canoes on Wheels” program, and headed down the river.

John and I paddled the sweep and lead canoes, while in the middle of the group paddled Ranger Joan, a representative of the National Park Service. Many folks who pass through this area and many who have lived here their entire lives have never realized that they have a National Park in their back yard. The Namekagon River is the major tributary of the St. Croix River, and is included in the National Scenic Riverway – a designation (along with National Historic Sites, National Monuments, and National Recreation Areas) administered by the National Park Service.

During a snack break, Ranger Joan shared the story of how Wisconsin Senator Gaylord Nelson grew up paddling on this river. It was through his love, foresight and hard work that the river is preserved in such wonderful condition for the enjoyment of all.

This overnight canoe trip was a collaboration between the Cable Natural History Museum and the National Park Service. Not only did Ranger Joan paddle with us, Ranger Jeff met us at the campsite and gave everyone a lesson in three different types of fishing. The presentation culminated with Tenkara fishing – a type of backcountry fly-fishing that originated in the mountains of Japan. Tenkara means “from the heavens” and refers to the way the line floats gracefully through the air and settles on the river’s surface.

After a lesson in knot-tying, Ranger Jeff opened his tackle box containing a rainbow of flies. Made from deer hair, feathers, and other materials, these lures mimic stoneflies, caddisflies, Mayflies, and other insects that fish like to eat. These flying insects are the adult stage of the same benthic macro invertebrates that the boys had sorted into ice cube trays in the morning. A healthy river should produce a healthy insect population – and good fishing! 

Around the campfire, Ranger Jeff read the boys a quote from President Lyndon B. Johnson, who established the National Wild Rivers System: “The time has also come to identify and preserve free flowing stretches of our great scenic rivers before growth and development make the beauty of the unspoiled waterway a memory.” Then Ranger Jeff asked the six bright-eyed boys, “What can you do to make sure this place will be here for the next group of kids that come back twenty, thirty, forty years from now?”

I have confidence that these young scientists, avid anglers, and budding outdoorsmen will be up to the task.

For over 44 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 13470 County Highway M. The new exhibit, STAR POWER: Energy from the Sun, opened in May 2012 and will remain open until April, 2013. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com/

Saturday, June 9, 2012

Tilt and Whirl

Bees drone lazily in the late afternoon sunshine. A rainbow of flowers blooms along roads, in gardens, and on Hawaiian shirts. Some of the shyer birds have quieted down, while vireos and thrushes still sing their hearts out on their breeding territories. Loons have fluffy chicks riding on their backs. Fox kits play and sun themselves outside the den. Mosquitoes buzz in your ears, and shimmering dragonflies come to your rescue.

In this season of growth and vitality, it is easy to forget how stunning the fall colors can be, or how the yard looked covered in snowdrifts. Every season has pleasant and unpleasant aspects, and they are all made possible by the tilt of the Earth on its axis.

The Earth’s axis is an imaginary line going right through the planet between the north and south poles. The axis is tilted 23.5 degrees off the plane of the Earth's orbit around the Sun. For several months of the year, the half of the Earth that’s tipped toward the Sun receives more direct rays than the other half. We are now absorbing more energy from the Sun than we will at any other time of year. Plants sense it, and they grow furiously – photosynthesizing like crazy – before cool weather and lower sun angles bring on winter dormancy again.

Without the tilt of the Earth’s axis, our day length would not change, Alaska would have perpetual twilight, and we would not have the wonderful variety of the four seasons. Instead, two slightly different seasons might emerge based on the distance of the Earth from the Sun. Our elliptical orbit takes us farthest from the Sun (to a point known as the aphelion) around July 3. The perihelion, or the closest point in our orbit, happens around January 4. The difference between the two distances is about 3,000,000 miles, a variation of only about 3%. This causes a fairly minor change in the amount of energy from the Sun that reaches Earth, and would not lead to our rainbow of seasons by itself without the tilted axis.

Although the word solstice derives from a combination of Latin words meaning "Sun" + "to stand still," the Solstice is not constant over the years. The tilt of the Earth’s axis changes by 2.4 degrees (between 22.1 and 24.5 degrees) over 41,000 years. We are comfortably in the middle of that range right now. When the Earth tilts less, the Sun is lower on the horizon in the summer and higher in winter. Thus, summers are cooler while winters are warmer. This changing tilt is one of several large-scale factors influencing the advance and retreat of glaciers.

Glaciers shaped our landscape, while the seasons decorate it. Both owe some thanks to the tilt of the Earth on our axis. While the tilt of the Earth has a big impact on our lives, that tilt may have been caused by a large impact itself. One theory suggests that a huge chunk of space dirt in the early solar system may have slammed into the still-molten Earth – ejecting material that would become the moon.

No matter what you believe, I hope you enjoy these long summer days, and sweet summer nights.

Happy Solstice!

A little bit of good in every bad

The peas are planted, the beans are watered, tomatoes are towering, and the basil is in. Gardening season has begun in full force, which means that I am feeling happier and smarter than I have all winter. This is not just an anecdotal “I love gardening” testimonial – there is scientific research to back up my claim.

During those long hot hours I spend toiling in the dirt, my body is synthesizing vitamin D. This fat-soluble compound is linked to depression prevention, immune system strength, bone health, and more. I cannot quite do photosynthesis like my tomatoes, but at least I can make something useful from sunlight!

It is not just the sunshine that makes gardeners so happy this time of year; it is also the fresh air. We inhale an elixir of happiness from the soil. A common soil bacteria – Mycobacterium vaccae – has been shown to increase serotonin (a happy chemical in your brain) levels in mice. Not only does this decrease anxiety, but it also makes the mice smarter! 

Mice given the bacteria navigated a maze twice as fast as the control mice. The effects do not last long, though, and scientists surmise that humans would need to be exposed about once a week in order to reap the benefits of these healthy bacteria.

Unfortunately, gardening season coincides with another season as well. Everywhere that clean, fast-flowing streams laugh and tumble down rocky paths, tiny larvae cling to the submerged surfaces of rocks and logs. At the business end of the tiny, worm-like creature is a pair of foldable fans. These fans strain passing debris from the fast-flowing water and the larva scrapes a snack into its mouth every few seconds.

After seven to ten days of eating and growing, this little larva will pupate (like a butterfly spinning a chrysalis). The creature spends a week in the pupa, completely rearranging its body and developing the tools for a new way of life. Then, in bubble of air, an adult black fly rises to the surface.

If it is a male black fly, we can pretty much ignore it. Males eat a little nectar, fertilize a female in flight, and die. Females may also use the sugary liquid to fuel their flight, but making eggs requires a blood meal. This is where gardeners, paddlers, hikers, anglers, and other outdoor enthusiasts come in. The black fly female will slash a little cut in your skin, inject an anti-coagulant with her saliva, and drink her fill.  No matter that her “fill” is approximately 0.00006 ounces, the bite’s ill effects loom much larger. We end up with bleeding, itchy, swollen welts around wrists, beltlines, necklines, hairlines, and ankles.

Nothing in nature is all bad, though.  These tiny tormenters feed tasty trout, beautiful birds, dashing dragonflies, and swooping swallows. Folklore claims that black flies pollinate blueberry flowers and improve fruit-set, but the scientific jury is still out on that one.

In Maine, the Black Fly Breeder’s Association sells humorous t-shirts and donates the money to charity. One t-shirt design lauds black flies as “defenders of the wilderness,” due to their ability to keep timid tourists at bay.

Despite the good qualities of black flies, we would all probably prefer to avoid them. Happily, they do not sneak indoors like mosquitoes, but indoors is not where the vitamin D and happy soil bacteria live. Dark colored clothing, carbon dioxide, and perfumes all attract them. So it follows that if we would like to deter black flies, we should wear white, not exhale, and not wash our hair or use deodorant. As a side effect, many friends and colleagues will avoid us, too.

After five or six hot days, the tender little bodies of black flies (one sixth of an inch long!) dry out and black fly season will be over.

Later in the summer, as my tomatoes ripen and the pea pods swell, I will be able to enjoy the sunshine and soil bacteria in an enlightened state of peace and happiness…interrupted only by the painful bite of horseflies.

Little White Flowers

The bright colors of newly opened flowers carpet the road ditches, and this makes riding my bike a little more dangerous. I am risking skinned elbows and broken bones as I crane my neck to attempt ride-by plant identification, or swerve onto the soft shoulder to get a better look.  It is worth it to greet old friends.

Sometimes in February when the ski tracks on the Birkie Trails are just perfect, I wish it could always be ski season. Then spring arrives in all its glory. In any season, I love seeing a delicate white dusting in the ditches and forests. Of course, right now the white dusting is flower petals instead of snowflakes.

Three species with white flowers stand out in my mind this week. Starflower is one. They are aptly named, since their white petals reflect light so brightly that they seem to glow from within, and overexpose any photo I take of them. This low plant has a whorl of lanceolate (long, narrow, but wider in the middle) leaves with many delicate veins. Up to three flowers seem to float above the whorl on slender pedicels. What makes this flower truly unusual is the number of petals. Sets of seven are very rare in nature!

Often growing nearby in the sun-dappled edges of northern woods are Canada Mayflowers, sometimes called False Lily of the Valley. A shady patch of their small oval leaves may bear no flowers at all. Sometimes just a few plants in a patch will grow a taller stem with two or three leaves and a spike of snowflake-like white flowers. The single leaves may help provide a “chosen plant” with the added energy it needs to bloom and set seed. Since the plants in a patch are clones connected by underground stems, all the little sugar factories can work together. As all hardy northern residents know, teamwork is necessary in the face of poor soil and short summers!

The third white flower that caught my eye has a couple tricks up its leaves, or rather, in the flowers themselves. Bunchberry is the smallest plant in the Dogwood family. With radiant white flowers in the summer and brilliant red bunches of berries in the fall, this common plant is always a treat to see. And it is more than meets the eye! The four white things masquerading as petals are actually sepals. We usually find sepals as the small green leaves cupping a flower. While the sepals of bunchberry flowers are unusually showy, the petals are unusually dinky.

Small though they may be, the cluster of tiny flowers bears petals designed like a catapult. When the flowers are ready, the lightest touch of a potential pollinator’s foot will trigger the petals to burst open in less than a millisecond.  This triggers the stamens to shoot up and fling pollen grains with the force of a huge explosive.

According to J. Edwards, et al, the authors of the original study published in the journal Nature:
“Bunchberry stamens are designed like miniature medieval trebuchets — specialized catapults that maximize throwing distance by having the payload (pollen in the anther) attached to the throwing arm (filament) by a hinge or flexible strap (thin vascular strand connecting the anther to the filament tip). This floral trebuchet enables stamens to propel pollen upwards faster than would a simple catapult. After the petals open, the bent filaments unfold, releasing elastic energy. The tip of the filament follows an arc, but the rotation of the anther about the filament tip allows it to accelerate pollen upwards to its maximum vertical speed, and the pollen is released only as it starts to accelerate horizontally.”

The pollen experiences 800 times the acceleration that the Space Shuttle does during liftoff, and is launched more than ten times the height of the flower.  From this lofty height of 2.5 cm, they can be more easily carried by the wind. Or the soaring pollen might smack into a bee and travel to a different flower that way. Bunchberries cannot self-pollinate, so this cross-pollination is necessary.

Flowers like these are worth a little swerving as I ride down the road. Those who are risk averse may choose to walk instead. In either case, drivers should be alert and give a wide berth to the many bikers and walkers out enjoying the wildflower gallery along our roadsides.

For over 44 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 13470 County Highway M. The new exhibit, STAR POWER: Energy from the Sun, opened in May 2012 and will remain open until April, 2013. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com/

Little Solar Panels

As the days get longer and the trees leaf out, spring ephemeral wildflowers race to soak in as much sunshine as possible. Spring beauties, wild leeks (ramps), Dutchman’s breeches, wood anemone, bloodroot, and trout lily are some of the most beautiful treasures of spring. They rush out of the ground each year, sometimes while snow still haunts the north-facing slopes. Flowers bloom, leaves unfurl, bees hum, ants crawl, seeds are set, photosynthesis produces sugars, starch is stored back into the roots, and then—just as the tree leaves above are reaching their full potential—the ephemeral leaves melt back into the duff.

Spring ephemeral wildflowers have figured out that they can make use of the rich soil in shady depths of deciduous forests, so long as they get a head start on the trees. Partly because they only show up for such a short time each spring, they have captured many a heart. They also capture many a photon.

Photons are little packets of energy that travel through space.  We know them as light. They carry energy from the Sun (released during nuclear fusion reactions) down to Earth. Once here, they provide almost all the energy for life on Earth. Plants, like these lovely spring ephemerals, are an essential link between the Sun and animals, since animals cannot capture sunlight on their own.

For just a few short weeks in spring, the flowers I mentioned above are absorbing photons like crazy, and using them to help split carbon dioxide from the air and water from the soil, and recombine those molecules into sugar.  Sugar is simply carbon, hydrogen, and oxygen.

This month, I am exploring the process of photosynthesis with first graders who come to the Museum for field trips. We act out a food chain starting with the Sun, and then shrink down so we can be magically transported into a leaf.  There we meet Chef Chlorophyll, the green pigment that mixes the ingredients of photosynthesis. The students race around the yard, gathering sunlight (yellow water), water (blue water), and air (drinking straws) to create a frothy green soup in the mixing bowl. Then we each eat a grape, and consider how plants produce the sugars that we eat every day in a hundred different forms.

The sugars produced by spring ephemerals are not distributed in sweet fruits, though. These plants mostly produce hard, dry seeds without the juicy cradle of flesh like apples and cherries. Instead, their precious sugars are stored as carbohydrates (complex sugars) in starchy roots. Burrow your finger into the soft soil near any of these plants, and you will soon pull out a small white tuber. The tubers of trout lilies and spring beauties have a mildly sweet flavor. Leek tubers store their sugar with an oniony kick. Dutchman’s breeches and bloodroots store their sugar with toxins added.

The spring ephemerals used the energy stored in these tubers to get a head start on the tree leaves this spring, and they are rushing to replenish their pantry for yet another year.

All summer long, other plants will be capturing the energy from photons of sunlight and storing it in their roots, stems, leaves, flowers, fruits and seeds. We harness that energy in a myriad of ways. Think about that as you eat you dinner salad, turn on the television, plant your garden, drive your car, and drink your morning coffee! Energy from the Sun is integral to every aspect of our lives.