Snowshoeing to Superior

Last weekend, we decided to take advantage of our beautiful, winter wonderland (which has since been destroyed by freezing rain courtesy of 21st century, climate-changed induced weather patterns!!) and go for an early morning snowshoeing adventure.  Wolf Ridge is about four miles inland from Lake Superior, and portions of the 275-mile Superior Hiking Trail go through our site.  I've never personally hiked from Wolf Ridge to the waterfront - this seemed like a great chance to do that.

The Superior Hiking Trail: great for hiking in the summer and showshoeing in the winter.

Snowshoes are kind of a culturally significant mode of transportation in our region because of their heavy usage by the Ojibwe.  Snowshoes, as it turns out, were invented simultaneously be many different ancient cultures that had to deal with walking around in the deep snow.  The basic principal behind snowshoes it that they increase the surface area of your foot so your body weight is being spread out, thus causing you not to sink as deeply into the snow when walking.  When I take students snowshoeing, they are often disappointed to discover that you do still sink into the snow.  However, when I have them walk around with one snowshoe on and one off, they can observe the big difference the snowshoes actually make.

It's hard work, though.  For our hike, we spent about three hours on snowshoes, and that alone took us over two hours.  We started by crossing Wolf Lake, the ice of which is past twelve inches thick by now.  (I had some students out on Wolf Lake this week and we got to listen to the booming of the ice, one of my favorite winter sounds).  Snowshoes slow you down, and your movements have to be much more deliberate.  Sometimes, as I watch a large group of people snowshoe across an open area, like Wolf Lake, I amuse myself by imagining that I'm observing a zombie attack.

Naturalists snowshoeing across Wolf Lake.

We use pretty modern snowshoes, made of metal and plastic.  Over the years, many different styles of snowshoes have been utilized and designed.  The Ojibwe used wood from black ash trees because of its general flexibility.  The wood was easily bent into the snowshoe-shape.  The webbing is made from woven moose rawhide, which is quite flexible before dried.  The presences of holes in snowshoes is important, as it allows snow to fall through the shoe.

A pair of Ojibwe-style snowshoes (image from: www.canadianoutdoorequipment.com)

After bushwhacking through a couple of cedar groves, we reached the Superior Hiking Trail overlook, a destination we often take students in snowshoeing classes.  From here, we can enjoy a great view of Lake Superior, pointing out the Apostle Islands on the other side of the lake and Palisade Head to the south.  At this point, we were exploring new territory for me, following the trail to the south.  It was a good hike, with a couple of incredibly steep climbs (this is part of section 13 of the SHT, which is known for its steep bluffs).  It was a relatively quiet morning as far as wildlife sightings, but we walked through some beautiful patches of cedar, aspen, and birch trees.

Enjoying the Superior Overlook.

Eventually, we reached highway 1, at which point we removed our snowshoes and walked the remaining mile along the road.  It was a steep final descent to Crystal Cove, the secluded Lake Superior beach-front at the intersection of Highways 1 and 61.  This was my first time to Crystal Cove in the winter, and it was pretty cool to see the snow and the waves coming together.  We made a small fire and enjoyed a snack.

Crystal Cove on a cloudy, winter day.

How we managed to get ten naturalists, their bags and snowshoes back home in a single vehicle is a whole other story.

Christmas Bird Count

The tall pines of Isabella, MN, make for a perfect winter wonderland landscape.

This past week, my return to the North Woods of Minnesota has been full of winter fun.  The snow came down non-stop for three days, creating plentiful opportunities for cross-country skiing, snowshoeing, boot hockey, and really terrible driving conditions.  On the 30th of December, I got to participate in a winter tradition that stretches way beyond the North Woods, or even Minnesota - the annual Christmas bird count.

At 9:00AM, I gathered with ten other birders in a small café in Isabella, MN, about twenty minutes inland from Finland.  There were ten teams total, comprising about 40 birders.  Together, our job was to survey a circle (15-mile diameter) around the Isabella township for all the birds we could see.  Each team was assigned a section of the circle, our team responsible for the eastern quarter.  This year, over 2,000 circles across the United States and Canada were or will be surveyed between December 14 and January 5.  The Christmas Bird Count is a citizen science survey, in that anyone who wants to volunteer can participate and gather data.  While the surveying techniques are not scientifically fool-proof, the data gathered from this survey for the last 113 years have been invaluable in a number of areas of ornithological research, especially conservation.

After assigning our areas to survey, I joined MJ (fellow Wolf Ridge second-year naturalist), Jenna (WR first-year naturalist), Carrie (WR staff member and marketing extraordinaire), and Margie (former WR naturalist and bird banding mentor) as we drove to a couple of different trails in our zone.  The morning mostly consisted of birding on foot as we hiked different areas, stopping frequently to look for movement and listen for bird sounds.  The trails we hiked were unbelievably quiet and still.  While hiking, we only spotted two downy woodpeckers all morning.  However, while driving back for our lunch break, we stopped and saw seven black-capped chickadees, two red-breasted nuthatches, two more downy woodpeckers, and a red crossbill (a new bird for me!) perched on top of a spruce tree, calling loudly.

Winter birding.

The downy woodpeckers were particularly exciting for us to spot because of some additional research that was taking place.  Some researchers are looking to learn more about what species of trees downy woodpeckers tend to feed on.  So when we spotted a downy woodpecker, we not only recorded the sighting, but also what species of tree it was perched on if displaying feeding behavior (hopping around, pecking at the tree, etc.)  For the record, we saw two feeding on birch trees, and two on dead aspen trees.

A somewhat blurry downy woodpecker feeding on a birch tree.

In the afternoon, I got to strap on some cross-country skis for the first time this winter and Carrie and I surveyed a trail that would have been otherwise inaccessible.  It was awesome to be back on skis and, even though the trail was not groomed for XC skis, a number of snow-mobiles had thoughtfully packed the snow down for us.  Again, a fairly still afternoon - one black-capped chickadee and three red-breasted nuthatches added to our list.  Nonetheless, it was a beautiful area to ski in especially as the sun started to set and the light hit the snow on the trees.

"Almost looks like a Dr. Seuss book." -Carrie Anderson

We spent the last hour car birding along some of the roads that we hadn't covered yet.  As night set in, we got to add two more birds to our list - two ruffed grouses perched high up in trees, silhouetted against the darkening sky.  At the end of the day, all of the Isabella birders gathered for lasagna and the sharing of our data.  In total 865 birds from 20 different species were counted, which is slightly lower than average for the Isabella area bird count.  Nonetheless, it was a great day of birding and enjoying the beautiful landscape created by the snowfall - the North Woods of Minnesota at its finest.

A ruffed grouse perched in the top of a tree at the end of the day.

Kinglets Keeping Warm

I'm in Duluth, and have been here all day, killing time until my 2:30 AM shuttle to the Twin Cities airport, from where I will fly home (currently located in McKinney, TX) to spend a couple of weeks with my family for the holidays.  Today, I've had the joy of experiencing the blizzard (more snow accumulated today than in the entire month of December 2011) from the windows of various coffee shops and fast-food restaurants.

Luckily, I had some friends to keep me company for most of the day.

While hanging out and sipping hot chocolates, I've been finishing up Winter World by Bernd Heinrich, which is all about how animals deal with the weather we're currently experiencing here (see earlier blog post about turtles).  His inspiration for this book was observing golden-crowned kinglets, little birds that spend winters in very cold places.  How do they do it?

The scientific name for the kinglet genus is "regulus," which means "little king," a reference to the fact that kinglets appear to have a crown on their heads.  In the case of golden-crowned kinglets, that crown is golden and, in males, with a tinge of fiery red.  Kinglets are an evolutionarily distinct group of birds, and there are two species native to North America, the other being the ruby-crowned kinglet (guess what color its "crown" is!)  The golden-crowned kinglets are found throughout North America and Canada, meaning that many spend their winters in blustery New England.  How does such a small bird survive such cold weather?

A male golden-crowned kinglet I removed from a mist net while bird banding at Hawk Ridge in September, 2012.

One incredible aspect of the golden-crowned kinglets' winter survival skills is that they begin nesting in late March and April, when snowstorms are still common in New England.  Their nests are built inside of coniferous trees, deep enough that the overhanging branches will protect the nest from snow.  Furthermore, if snow covers a tree containing a nest, it adds an insulating layer from the cold.  Kinglet nests have been observed to contain a number of materials, one of the most common of which is grouse feathers.  The grouse feathers are the perfect size and shape to add significant warmth to the nest.  When it comes time to lay the eggs, kinglets lay 8-11, so many that they typically have two layers of eggs in the nest.  Furthermore, as soon as the hatchlings are old enough to stay warm on their own, a mother kinglet will get to work on a second nest, where she will lay another brood, a phenomenon known as "double clutching."  This sounds challenging, but 80% of kinglet hatchlings survive!

In order to keep their metabolism high enough to stay warm in the cold months, golden-crowned kinglets spend dawn until dusk foraging for food nonstop (the male apparently foraging for the female while she is on the nest).  The fat reserves they accumulate from this amount to about 0.3 grams, not nearly enough to survive a cold, winter's night.  How these 5-6 gram birds do that is still shrouded in mystery.

The two most likely spots a kinglet could lose heat is through the eyes and beak - thus, one simple method to keep warm is burying their "faces" in feathers when sleeping.  Also, kinglets appear to travel in groups of two or three.  Three kinglets huddling together during a cold night would prevent up to 37% of the heat loss they may otherwise experience individually.  However, it seems that the most important factor to keeping kinglets warm at night is shelter.  Where exactly they go is the question.  Heinrich suspected they were staying in abandoned squirrel nests, for example.  However, after following groups of kinglets near his cabin in Maine, it appeared that the kinglets did not have one set place to stay warm overnight.  Rather, because the kinglets were foraging until the moment it got dark, they were finding many different places to stay based on where they were when the sun set.

As I watch the snow falling outside the window of this cozy coffee shop, it is amazing to me to imagine a five-gram bird trying to stay warm out there tonight.  It doesn't surprise me that our knowledge of how they accomplish this is still minimal.  At the end of the day, I think Heinrich says it best: "They defy the odds and the laws of physics, and prove that the fabulous is possible."

Turtles in the Winter

In thinking about my turtle story that inspired this new blog, I realized that, while it's a story I enjoy sharing, I know little about the biology behind it.  Yes, I'm aware that turtles hibernate under the ice and sometimes in the mud all winter long, but just how does a turtle survive such long, cold months?  How exactly do reptiles hibernate?

Luckily, the book I'm currently reading, Winter World by Bernd Heinrich had some answers.  In short, turtles are some of the most resilient creatures in the world, which makes sense if you think about how long they've been around.  Relative to most other animals, turtles evolved quite a long time ago.  It's possible that turtles lived right through the "global winter" of 64 million years ago that took the lives of many dinosaurs, so a measly six-months under the frozen ice is comparatively nothing.

One cool features turtles have to keep themselves alive is blood that acts as an anti-freeze.  Some turtles' bodies will completely freeze, but their internal organs are protected because the blood pumping through their bodies won't become frozen.

A painted turtle, frozen for the winter.

However, a greater problem exists in a turtles' need for oxygen.  While most animals that spend the winters under the ice have gills, turtles breathe with lungs and need a constant supply of oxygen.  Cold water retains oxygen better than warm water, so that helps.  Aquatic plants can photosynthesize and produce oxygen in the water too, but as soon as snow covers the top of a frozen lake, the plants can no longer get the sunlight they need and the rotting vegetations sucks the oxygen right back up.  The question of how turtles get their oxygen continues to stump researchers, but there are some studies out there that might provide us with some helpful clues.

One study led by Gordon R. Ultsch in 2000 investigated a colony of map turtles (Graptemys geographica) in the Lamoille River and Lake Champlain in Vermont.  They found that in winter, once the water drops to temperatures of 2-degrees-Celsius, the turtles simply pile themselves on top of each other deep at the bottom of the lake, and there they remain from November to March.  The researchers removed the turtles once a month to measure their blood acidity, lactate, oxygen, and carbon-dioxide levels.  As it turns out, the turtles remain aerobic (breathing oxygen) throughout the entire winter, simply by significantly lowering their metabolism.  This is possible because of their lack of physical movement and low body temperatures.  Furthermore, all the map turtles rested with their legs and heads fully extended, which seems to act as a way to maximize skin exposure to take up oxygen in the water.

In contrast to the map turtles, painted turtles (Chrysemys picta) hibernate in shallow water.  The advantage here is that shallow water heats up sooner in the spring, thus triggering the end of the hibernation period in the turtles.  A shorter hibernation period means a less intense impact on the metabolism.  However, shallow hibernation increases exposure to predators such as raccoons.  Painted turtles deal with this by burying themselves in the mud, but this cuts off all exposure to oxygen in the water.  It's all a trade-off.  Deep water means a longer hibernation but more available oxygen while shallow water means a shorter hibernation but with less oxygen available.

Like I mentioned, at the end of the day, the lesson is that turtles are resilient.  Hibernation takes a huge toll on their bodies, but it has worked for them for millions of years.  It's easy to forget all that's happening under the layer of ice on the lakes in winter.  If you're a turtle, it's a great place to be, but it certainly comes at a cost.