Can I eat that?

Some students in a 4th grade classroom asked a very good question yesterday.  They have been reading the book Hatchet by Gary Paulsen.  In the book, the main character Brian observes birds eating some berries and decides that they are safe to eat based on that observation.  They wanted to know if you see a bird eating berries, does that mean that those berries are safe for you to eat?

Cedar Waxwings eating the fruit from Eurpoean Buckthorn and Riverbank Grape

Fruits and berries can be placed into three categories. Some of them are edible (can be eaten) for people, some of them are inedible (may taste bad or cause sickness), and some are toxic (highly poisonous).  Birds commonly eat fruits from all three of these categories.  A bird eating a fruit or berry does not mean that it is safe for you to eat.

Let me repeat that:  A bird eating a fruit or berry does NOT mean that it is safe for you to eat!

Would you eat this berry if you found it in the woods?
 

Watch the Winter Olympics!

A break away from the usual science and nature blogging to remind everyone that the XXII Olympic Winter Games are currently taking place in Sochi, Russia.

I love the Winter Olympics.  I was too young to remember the 1980 Lake Placid Games, but since the 1984 Sarajevo Games I have eagerly awaited the arrival of each Winter Olympics.

The Winter Olympics feature few sports that are familiar to most Americans.  Most of the sports are never shown on the major American broadcast networks with the exceptions of ice hockey, alpine skiing, figure skating, and snowboarding.

But, once very four years we are reminded of other winter sports such as bobsled, luge, cross country skiing, ski jumping, skeleton, etc.

My favorite moment of the Olympics so far this year was watching 40 year old Ole Einar Bjørndalen win a Gold medal in the 12.5km Pursuit (Biathlon).  This marks Bjørndalen's 7th Olympic Gold medal (and 12th medal overall) in the biathlon.  He has competed in every Winter Olympics since the 1994 Games in Lillehammer, Norway. In 2002, at Salt Lake City, Bjørndalen won four Gold medals. Since then he has been on of my favorite Olympians.

For those that don't know, biathlon combines cross country skiing and target shooting with a small bore (.22 Long Rifle) rifle.  Imagine skiing as fast as you can then coming to a complete stop to shoot at a target 50 meters away that is no more than 4.5 inches wide from the standing position or 1.8 inches wide from the prone position.  Then go immediately back to skiing at full effort.  To make it worse, if you miss a target you have to complete a lap around a penalty loop - one loop for each shot you miss.

Another exciting moment (to me at least) was watching long track speed skaters form the Netherlands go 1-2-3 in the Men's 5000m.  I also got a thrill from watching the greatest Olympic wrestler of all time Aleksandr Karelin carry the Olympic torch during the opening ceremonies.

I eagerly anticipate the rest of these Olympic Games.  I hope everyone will tune in to watch the games and support the athletes from every country as they pursue their Olympic Dreams.  Unlike professional athletes in basketball, football, and baseball, most of the athletes in these sports will never become rich.  Many of them work other jobs during the year to support their participation in the sport.  They compete for the love of their sport.  Passion like this is something to aspire to.  In other countries besides the United States, Olympic competitors and especially Olympic champions are celebrated as national heroes.  Unfortunately, this is something we do not do very well in the United States - once the games are over these athletes go back into the shadows where they continue to work to improve so they can represent their country int he sport they love.  These men and women should be revered for their athletic prowess and devotion to something that they love. 

Watch the Olympics!  Be a fan and supporter of all Olympic athletes.

Standing in the middle of the river...

I have been looking back at my photos from past years to find something interesting to share and I came across a set of images from 02 February 2009.  I remember taking these photographs because of the unique circumstances.  A few days earlier, on January 27th, I had visited the Chippewa Watershed Conservancy's Sylvan Solace preserve. 

I remember the temperature on January 27th was very cold for Mid-Michigan.  Looking at weather records for that date show a low temperature of about -5 degrees Fahrenheit at 9:00AM.  I snow-shoed from the parking area along the River Loop.  Even with the cold air temperatures, the river was flowing freely with only a little ice along the edges.  Because the river was warmer than the air temperature, vapor was rising up and condensing in the air over the river.  Some of it was forming hoarfrost on trees along the river.  A mostly sunny sky made for some nice pictures.

I took several pictures and an idea formed in my head.

Knowing Nature

Pop Quiz time!

Take out a piece of paper.

I want you to write the names of 100 species of plants or animals.  One rule:  every plant or animal must be native to the region in which you live.

This means no pets, farm animals, or zoo animals are allowed. 

The plants have to be native plants too.  This means no houseplants, no garden plants, no agricultural crops.

Be specific... What species of oak tree, bat, deer, mouse, etc.?

Can you name 100 species?

Here in Michigan, there are a vast number of species to choose from. 

The Field Manual of Michigan Flora lists over 2,700 species of plants.

The Michigan Audubon Society lists over 350 species of birds on its state checklist.

There are currently 66 species of mammals found in the Michigan.

Fifty-two species of reptiles and amphibians can be found in the state.

The Michigan DNR also lists 153 species of fish.

The insect species in the state number in the thousands.

It seems like it should be easy to name 100 native species, but a majority of people probably can't.  Try it and see.  Let me know if you can name 100 species for your area.

Next stop, the Subnivean Zone!

Last week I wrote a post about the winter habits of the Eastern Cottontail Rabbit.  In this post I mentioned that some smaller mammals make use of a space called the subnivean zone.  The word subnivean comes from the Latin root words sub "under" and nives "snow" - so subnivean translates to "under the snow".

The subnivean zone is mostly hidden from humans.  We might look at a snow covered field and see this.

A snowy field with evidence of rabbits.

Rabbit tracks, feeding evidence, and scat only show part of the story about what is going on in the field.  The snow in this picture is more than 12 inches deep.  The rabbit that left its tracks was only interacting with the surface.  More of the story is buried under the snow.

Try this some time.  Wait a few days after a snowstorm and then go find a grassy field that is covered with more than six inches of snow.  Look for an area with no visible signs of animals.  Take a flat shovel and scrape off the top inch or two of snow from a path six feet long (make sure you don't step in the path of your shovel).  You may not find anything unusual at this level.  Continue scraping off layers of snow from this path.  At some point the path you shovel will probably intersect a horizontal tunnel through the snow.  This tunnel will probably be about 1 - 1.5 inches across. 

Found it - a tunnel in the snow

 
Once you find one of these tunnels, gently use your shovel to follow the tunnel.  Scrape snow from the surface along the direction of the tunnel to expose it to the surface.  Be careful not to fill in the tunnel with the snow you are removing.  This tunnel will likely travel for many feet in one direction.

The subnivean world - tunnels within the snow.

Sometime those tunnels will intersect with perpendicular tunnels.  In other places the tunnels will go vertical with a shaft rising to the surface or diving downward to the ground.

The subnivean world - cross-tunnels and vertical shafts.

Find one of the spots where the tunnel drops vertically to the ground.  Dig downward at this point until you come to the bare ground.  Look closely at the sides of the hole that you just dug.  The snow is probably not the same density from the top to the bottom.  The upper few inches are probably fluffy and not compacted.  At the level where you found the horizontal tunnels, you will probably find that the snow has formed a hard crust.  This crust usually forms the floor of the tunnels.  Below this crust, the snow will often be densely compacted.  In areas without vegetation, this layer of compacted snow may go down all the way to the upper surface of the soil.  In areas a dense covering of plants, the vegetation will suspend the snow up above the level of the soil.  A lens of ice will form at this level, supporting the layers of snow above - creating a space between the snow and the surface of the soil.  This space is the true subnivean zone.  This subnivean zone will not be free of ice and snow.  Hoarfrost often develops here as water vapor rising from the soil hits the ice lens where it freezes.

A hole dug through 12+ inches of snow to reach the subnivean zone.

Here is the same image with the lines to show the crust and ice lens.

The subnivean world - snow crust (blue line) and ice lens (red line)

So what animals are creating these tunnels and using the subnivean world?  In Mid-Michigan, the most likely suspects are several species of mice and voles (kind of like a chubby mouse with a short tail).  Other animals will use the tunnels to hunt including shrews and sometimes weasels.  Even with this intrusion by predators, the subnivean world provides  freedom of movement and safety to the rodents that utilize it.  Mice and voles can move about this zone without being seen from above - they can still be heard and sometimes you will find where a fox or owl has intruded feet first into the subnivean zone to snatch a meal. 

This zone can also substantially warmer than the world above the snow.  The snow and ice eliminates the effects of windchill to the inhabitants of the subnivean zone - allowing them to retain more heat than they would if they were  inches trapped above the snow.  Snow is a great insulator and the layers of ice within the snow prevent heat from the earth from rising upward, creating a pocket of warmer air trapped just above the soil's surface.  When I was taking these pictures I sunk my shovel down into the soil with no resistance - the ground in this field has not frozen.  In areas where the snow cover is thinner (or nonexistant) the two months of cold temperatures have caused the ground to freeze to a depth of 6 inches or more. 

So next time you go outside and think that those barren snow-covered fields are devoid of life you will know that there is a whole world going on within and under the snow.

The subnivean world - tunnels criss-crossing within the snow.

Welcome to the Sunbivean Zone...

Two boulders, both alike in dignity...

Last month I wrote several posts about geologic concepts (cross-bedding, original horizontality, and superposition).  Every photo that I shared in those three posts was of sedimentary rocks (sandstones and shales).  This focus on sedimentary rocks was not intentional - I did not intend to ignore the fans of igneous rocks and metamorphic rocks.  In order to make up for this oversight, and to restore peace in the geologic community, I would like to share an image of a igneous rock and one of a metamorphic rock.  Both of these photos were taken over this past summer during my vacation to Maine.

The first rock is a granite boulder with a very coarse texture.  The size of the crystals in this boulder indicate that the magma that formed this rock cooled very slowly, deep below the surface of the earth, allowing large crystals to form.  Three minerals can be easily seen in this boulder:  black crystals of Biotite Mica, smoky gray Quartz, and large tan Feldspar crystals.

A coarse granite boulder

The second rock is a boulder with metamorphic origins.  Metamorphic rocks are rocks that have been changed from one rock type to another by intense heat and pressure (or through chemical interactions).  This boulder is composed of a type of rock known as Ellsworth Schist.  The dark grayish-green rock is called Chlorite.  The pale layers between the the Chlorite are bands of Quartz or Feldspar.  The layering within the rock is called foliation.  Foliations form when the the pressures that cause the rock to metamorphose are unevenly applied.  The folding within the foliations show that this rock was subjected to further pressures perpendicular to the plane of the foliations.

Details of a Ellsworth Schist boulder

I predict...

Yesterday was Groundhog Day.  Groundhogs are in short supply in Mid-Michigan during the middle of Winter, but I went outside and saw my shadow.  Therefore, I predict that winter will end in six weeks,  exactly when it is supposed to, on the Vernal Equinox (March 20th).

This Groundhog saw its shadow back in June 2013.