Seasonal Changes and Amazing Adaptations

Seasonal Changes and Amazing Adaptations: Click for a larger view of a Dark-eyed 'Oregon' Junco Male, Junco hyemalis montanus, Courtesy and copyright 2008 Ryan P. O'Donnell
Dark-eyed Junco “Oregon” Male
Junco hyemalis montanus
Courtesy & © 2008 Ryan P. O’Donnell 

Biking daily from Smithfield Canyon to USU campus, combined with an early am run, I’m well aware of the drop in temperatures, as are those of us who find themselves outdoors on a more permanent schedule. I’m speaking of our relatives who reside in the wild- birds, trees, raccoons, and such.

While I put on an extra layer or two, plants and animals have far more sophisticated adaptations from behavioral to physiological to structural.

We are all aware of the marvelous migration and hibernation behaviors, so let’s add a few more amazing adaptations to the list.

I’ll begin with a bird that is very common at our winter feeder- the Dark-eyed Junco. which responds to the first shortening days of summer with a series of physical changes: its reproductive organs become inactive and shrink in size, hormones stimulate the rapid growth of a new set of feathers, and fat deposits develop to provide fuel for the long migratory flight ahead.

Thus the preparation for migration starts as soon as the days begin to shorten. And the process must operate in reverse when the bird is in its winter habitat in the United States. As soon as days begin to lengthen, the Dark-eyed Junco must gear up physically for the flight north and breeding season. If it fails to do so, it likely won’t survive a long-distance migration. So the cycle of life and its related migrations and transitions are deeply connected to the heavens.

Plants are no less amazing. Those in temperate zones must also set their calendars accurately in order to flower and, for deciduous species, develop and drop leaves at the optimal time. Plants set their internal calendars using several attributes from the sunlight they receive. In fact, the angle of the sun may be more important to a plant than day length.

That’s because plant cells produce compounds called phytochromes in response to different portions of the light spectrum. Direct sunlight is higher in red light, while indirect sunlight contains more far-red light. During late fall and early winter, when the sun remains low in the southern sky, the indirect light produces an increase in far-red phytochromes.

As spring approaches and the arc of the sun rises in the sky, direct sunlight triggers the production of red phytochromes. The ratio of these two compounds mediates the hormones involved in flowering, leaf drop, and bud development. Even seeds below the soil are affected. The amount of red and far-red light that penetrate the soil is sufficient to govern germination.

Some behavioral alterations worth mention beyond migrating and hibernation are herding and flocking, huddling to share body warmth, dietary change, hair & feather change- both color and structure, and many more but my radio time is ending, so now it’s your turn to explore more! It really does make you appreciated the wonders of nature.

This is Jack Greene for Wild About Utah.

Image: Courtesy and copyright 2008 Ryan P. O’Donnell
Text:     Jack Greene, Bridgerland Audubon Society

Additional Reading:

Dark-eyed Junco, Junco hyemalis, Aynsley Carroll, Animal Diversity Web,

Dark-eyed Junco, Junco hyemalis, Aynsley Carroll, Boreal Songbird Initiative,

Jigang Lia, Gang Lib, Haiyang Wangb, and Xing Wang Denga, Phytochrome Signaling Mechanisms, The Arabidopsis Book, American Society of Plant Biologists, 2011, pdf

Best Snow

Click to view larger image of a skier at Brian Head, Photo Courtesy USDA Forest Service
Skier at Brian Head
Photo Courtesy USDA Forest Service

As the mountains begin to take on hues of scarlet, gold and russet, many Utahns might be looking eagerly toward the coming months when those slopes will be blanketed in white. The Utah ski industry nurtures a whopping annual income of about $800 million dollars. It’s no surprise, therefore, that the state claims to have the “greatest snow on earth.” In fact, the state of Utah managed to make their slogan a federal trademark in 1995 after winning a lawsuit brought by the Ringling Brothers and Barnum & Bailey circus group, who felt the catchy marketing phrase might be confused with their slogan, the Greatest Show on Earth.

The trademark must have worked, because Utah draws so many visitors to its slopes, it racks up about 4 million skier days annually. But disregard plenty of evidence that we do indeed draw a crowd, and the statement is pretty subjective. So what’s the science behind our legendary powder?

The ideal condition skiers hope for is a deep, fluffy snow that creates the illusion of bottomless powder. And finding it is a bit like the Goldilocks story. Too wet, and you bog down. Too dry, and there’s not enough body to create a floating sensation beneath the ski. If the terrain is too steep, the powder won’t stick. And if it’s not steep enough, you can’t build sufficient momentum to glide over the top.

To get to the bottom of why Utah’s snow is just right, we actually have to look even further westward, toward the slow warm waters of the North Pacific current. As water laden clouds move inland, snow first falls over the Cascades in the north and the Sierra Nevadas further south, with an average moisture content of 12%. Even in areas like Washington’s Mt. Baker, where annual snowfall comes in greater quantities than Utah, the moister maritime snow creates a heavy base that bogs down skis. By the time these winter storms cross the Great Basin and reach the skiers’ Mecca of Alta and the Wasatch Range, the moisture content will have decreased to about 8.5%. And that seems to be the sweet spot. The moisture content of Utah’s intermountain snow is just enough that powder from our first storms settles into a soft but voluminous base. As winter progresses, fresh snow falls in a cold and mostly arid environment, forming very fine, symmetrical crystals called dendrites. The microscopic structure of dendrites allows them to accumulate in well ventilated, incompact drifts, much like the puffy down in your favorite pillow or ski jacket.

And perfect powder isn’t the only advantage Utah’s ski resorts have over their neighbors. Our mountainous topography, with its wealth of winding canyons, means we have an abundance of slopes well protected from strong winds which could compact or carry away fresh snowfall. And while so many cold and overcast days might get you down, it also protects our top powder from radiation and air mass effect, which can create a crust along the surface. And that means our freshly fallen powder sticks around for longer.

So consider that Utah offers 26,000 acres of mountain, blanketed in more than 500 annual inches of perfect intermountain snow, and it’s no wonder we enjoy 5 times the number of “powder days” as our neighbors. “The Greatest Snow on Earth” starts sounding a lot less subjective, and more like truth. In fact, you just might be tempted to make like Goldilocks and make yourself at home.

For Wild About Utah and Stokes Nature Center, I’m Ru Mahoney.

Image: Courtesy USDA Forest Service,
Text:     Ru Mahoney, Stokes Nature Center in Logan Canyon.

Additional Reading:

The Smell of Rain

Electron micrograph showing
the filamentous structure of
Photo Courtesy:
Soil Science Society of America

Spring is my favorite season. I love watching our landscape turn from brown to green, the first butterfly sighting, and the rain. During a recent April shower, I stepped outside and inhaled that magical springtime scent – the smell of rain. Which got me thinking – what is that smell, anyway?

What seems like a simple question, begs a complicated answer. That smell, however, does have a name – petrichor – and there are many things that contribute to its scent. One of the biggest culprits may actually be soil bacteria – mostly from the genus actinomycetes – which grow in unfathomable concentrations in soils all around the world. These bacteria play an important role in decomposition and soil health. Periods of relative dryness trigger their reproductive cycle, causing the production of spores, which are considerably more drought-tolerant. When rain finally does fall, the spores are launched into the air, where they may eventually reach our nose. Scientists have identified the chemical compound responsible for the spore’s odor and have named it geosmin, which literally translates to ‘earth smell.’

Humans noses are particularly sensitive to geosmin, but we’re not the only ones. Camels, too, are sensitive to its smell and some scientists believe this helps them find oases in the desert. Our ability to detect this odor might be a throwback to our nomadic ancestors for whom finding water in a vast landscape was of utmost importance.

But the scent trail doesn’t end with geosmin. The chemical compound ozone may also be a part of petrichor especially after a thunderstorm, as ozone is produced by lightning. Another aroma is provided by chemicals called volatile oils which are produced by all plants, and which collect on the ground during dry periods. With rain, they evaporate into the air, contributing to the musty, earthy odor. Acidic rain has also been shown to create scents by reacting with chemicals on the ground such as spilled gasoline. And further complicating the matter is the fact that rain hitting the earth throws dust and other particles from countless sources into the air.

If all of these smells are around us all the time, why is it that they are distinctly associated with rain? The answer lies in the properties of odors and how they travel. Everything that produces a scent is releasing chemical compounds into the air. The ability to evaporate – or volatility – of these compounds increases with the heat and moisture levels of the air around them. The humid air that produces rain creates ideal conditions for conveying scents to our noses.

In the end, it’s not the rain itself that causes odor, but the interaction of water and a number of chemical and organic compounds. Test this theory at home by throwing a bucket of water on the lawn or a hot driveway to see if you can recreate the smell of rain. Likewise, smell a stick, leaf, or rock when it is dry, then wet it and see how the odor changes. For those seeking answers to the origins of the smell of rain, it’s often best to follow your nose.

Thank you to the Rocky Mountain Power Foundation for supporting the research and development of this topic.

For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.

Images: Photo Courtesy Soil Science Society of America
Text:     Andrea Liberatore, Stokes Nature Center in Logan Canyon.
Special thanks to Joel Martin from the Utah Climate Center

Additional Reading:

National Public Radio (2007) The Sweet Smell of Rain. All Things Considered, August 11 2007. Interview of Dr. Charles Wysocki by Debbie Elliott. Transcript available online at:

Gerritsen, V.B. (2003) The Earth’s Perfume. Protein Spotlight, Issue 35. Accessible online at:

Gerber, N.N, and Lechevalier, H. A., (1965) Geosmin, an Earthy-Smelling Substance Isolated from Actinomycetes. Applied Microbiology. 13,6. Accessible online at:

Live Worldwide Network for Lightning and Thunderstorms in Real Time, Blitzortung,


A free-falling snow crystal photographed as it fell on Alta Ski Area on March 6, 2011, Photo Courtesy & Copyright Tim Garrett, University of Utah
A free-falling snow crystal
photographed as it fell
Alta Ski Area on March 6, 2011
Photo Courtesy & Copyright 2011
Tim Garrett, University of Utah
Alta Snowflake Showcase

Snowflake, Photo Courtesy and Copyright A free-falling snow crystal
photographed as it fell
Alta Ski Area
March 6, 2011
Photo Courtesy & Copyright 2011
Tim Garrett, University of Utah
Alta Snowflake Showcase

A stellar dendrite snow crystal, Photo Courtesy and Copyright Kenneth Libbrecht, Caltech University, A stellar dendrite snow crystal Photo Courtesy & Copyright
Kenneth Libbrecht, Caltech University

A stellar dendrite snow crystal, Photo Courtesy and Copyright Kenneth Libbrecht, Caltech University, A stellar dendrite snow crystal Photo Courtesy & Copyright
Kenneth Libbrecht, Caltech University

A hexagonal plate snow crystal, Photo Courtesy and Copyright Kenneth Libbrecht, Caltech University, A hexagonal plate snow crystal Photo Courtesy & Copyright
Kenneth Libbrecht, Caltech University

As winter draws to a close, I’d like to take a moment to reflect on the amazing weather phenomenon that is a snowflake. When winter weather dumps inches of snow on us, it’s easy to overlook the tiny works of art, those intricate and delicate snowflakes, which make up the storm.

Snowflakes – or to use a more scientific term, snow crystals – come in a variety of different shapes including long, thin needles, flat hexagonal plates, columns, and irregularly-shaped pellets called graupel. The International Snow Classification System recognizes ten different shapes in all, only one of which is the traditional snowflake image. The classic six-armed snowflake shape is called a ‘stellar dendrite’ by scientists.

When teaching programs about snow, someone inevitably asks me, “Is it really true that no two snowflakes are alike?” As far as I can tell, the answer is, well, ‘maybe’, and here’s why.

Three things are needed to form these intricate crystals, and the first two are fairly obvious: water, and temperatures below freezing. The third item is a little more inconspicuous. Water cannot condense and freeze all on its own. Every snowflake needs a piece of atmospheric dust or salt at its core. This particle is referred to as a ‘nucleating agent,’ and it attracts water molecules which then condense and begin to freeze. From there, a snowflake’s overall shape is determined by a number of other variables including the atmospheric temperature, the amount of available moisture, wind speed, and mid-air collisions with other snowflakes.

To add more complexity, consider that each individual snowflake contains somewhere on the order of 10 quintillion water molecules. That’s ten with eighteen zeros behind it. While the way these molecules bind to each other is dictated by the laws of physics, the sheer number of ways in which 10 quintillion water molecules can arrange themselves as they freeze into place is mind boggling. But then again, how many snowflakes do you think fall in the typical March snowstorm in Utah? A lot. One scientist has estimated that the number of individual snowflakes that have fallen on Earth in the planet’s history is ten with 34 zeros behind it. In all of those snowflakes is it possible that two are exactly alike? Yeah, maybe… but good luck finding them!

For more information and some beautiful snowflake photographs, please visit our website at Thank you to the Rocky Mountain Power Foundation for supporting the research and development of this Wild About Utah topic.

For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.


Photos: Courtesy Tim Garrett, University of Utah,
Kenneth Libbrecht, Caltech University
Text: Andrea Liberatore, Stokes Nature Center

Additional Reading:

Halfpenny, J.C and Ozanne, R.D. 1989. Winter: An Ecological Handbook. Boulder, CO: Johnson Books,

Gosnell, Mariana. 2007. Ice: the Nature, the History, and the Uses of an Astonishing Substance. Chicago, IL: The University of Chicago Press,

Libbrecht, Kenneth .1999. A Snowflake Primer: the basic facts about snowflakes and snow crystals.