12 September 2014

Guest Post: Mystery Butterfly

Observations & photos submitted by naturalist Kim Birck, late July 2014.

Yesterday a butterfly I’d never seen before visited my yard. It had the colors of a swallowtail, but no tails, and it didn’t match anything I could find by doing a Google image search for “black and yellow butterflies." So I posted a (low-resolution) smartphone photo to Facebook and got an immediate reply from a cousin in Wisconsin--“Could it be a Mourning Cloak?” Though the Mourning Cloak is Montana’s state butterfly and does frequent my yard--and its general morphology is somewhat similar--I’d already ruled out Mourning Cloak using the eNature.com online butterfly field guide.  

However, eNature was no help in figuring out who the mystery visitor actually was. The categories I might have chosen from their list--swallowtails or “boldly patterned”--produced no results. This was a very cooperative butterfly, however, hanging around all day and posing prettily on the bee balms (Mondarda sp.) that have proliferated where the native vegetation catches overspray from the lawn sprinklers. So I was able to get several good shots with a real camera, and e-mailed one to my friendly local naturalist at the Montana Natural History Center, Brian Williams. 

Twelve hours later, I had a reply: “Hi Kim, Great picture and good butterfly--it's a female Great Spangled Fritillary. Charles [Miller] and I were out in the Rattlesnake yesterday and saw one ourselves! Perfect timing on your question too, I've been working on my fritillary ID skills the last two weeks.” 

I Googled Great Spangled Fritillary, and on the Wikipedia page found the reason why it was so hard to identify: “Females tend to be darker than males and individuals from the western reaches of this species range tend to be brighter orange.” Talk about an understatement! All the Great Spangled Fritillary images I’d ever seen were brown and gold. Who knew the sexes were practically dimorphic? Today, a couple orange-colored males were chasing each other around the yard, and one landed on the same flower as the female I was photographing. She took off, but here’s the male.

He appears a bit the worse for wear as the markings have faded, near his wingtips, especially. 

Here are views of the undersides of their wings: Male:

and Female:

After seeing them fluttering around, I had a few more questions for Brian: 

"How do you distinguish Great Spangled from the OTHER Fritillaries? Could GSF be easily confused with the Northwestern Fritillary?" 

He responded: "Well, identifying the fritillaries besides Great Spangled is my summer's million-dollar question. Luckily, the Great Spangled is the one (of 10 or so, it seems), that is most readily identified. The best characteristic is the nature of the silver spots on the bottom of the hindwing--in the Great Spangled, the spots are relatively few, small, and well-spaced compared to all the rest of the fritillaries (like your photo, which is indeed a Great Spangled). The Great Spangled is also a bit bigger than all the other fritillaries. So, while at first glance, the Northwestern and Hydaspe Fritillaries are similar to Great Spangled in overall color, it is possible to distinguish them in the field. Beyond Great Spangled, the question is much more muddied. Charles and I have been collecting fritillaries for a display and I've actually been submitting photos of our pinned specimens to the website 'Butterflies and Moths of North America' to get positive identifications. Good fun!"

(Now we know what naturalists do when they aren't leading field trips!) 

Natural History Information from the Butterflies and Moths of North America Website
Great Spangled Fritillary 
Speyeria cybele (Fabricius, 1775) 
Family: Nymphalidae 
Subfamily: Heliconiinae 
Identification: Large. Upperside of male tan to orange with black scales on forewing veins; female tawny, darker than male. Underside of hindwing with wide pale submarginal band and large silver spots. 
Wing Span: 2 1/2 - 4 inches (6.3 - 10.1 cm).
Life History: Males patrol open areas for females. Eggs are laid in late summer on or near host violets. Newly-hatched caterpillars do not feed, but overwinter until spring, when they eat young violet leaves. 
Flight: One brood from mid-June to mid-September. 
Caterpillar Hosts: Various violet species (Viola). 
Adult Food: Nectar from many species of flowers including milkweeds, thistles, ironweed, dogbane, mountain laurel, verbena, vetch, bergamot, red clover, joe-pye weed, and purple coneflower. 
Habitat: Open, moist places including fields, valleys, pastures, right-of-ways, meadows, open woodland, prairies. 
Range: Alberta east to Nova Scotia, south to central California, New Mexico, central Arkansas, and northern Georgia. 
Comments: The most common fritillary throughout most of the eastern United States. 

18 March 2014

Under the Microscope: The Spring Equinox

This time of year, as the last snow melts from yards and mountainsides, I always find myself getting excited for the spring equinox, which happens to be this Thursday, the 20th.  Although picnics and gardening may be weeks or even months off yet, the spring, or vernal, equinox marks the point in the year that daylight hours will start to become longer than nighttime hours.  No matter how many snowstorms happen between now and June, I take comfort in knowing the days are finally becoming longer than the cold winter nights had been.

Technically, the equinoxes occur when Earth’s orbit and axis tilt cause the Sun to pass directly over the equator, shining its light equally on the northern and southern hemispheres.  This has the effect of giving most places on Earth roughly 12 hours of daylight and 12 hours of night, which is where the term “equinox” comes from:  in Latin, “equi” means equal and “nox” means night, making it literally “equal night.

The Equinoxes only happen twice per year, around March 20th and September 22nd, and mark the generally accepted beginnings of spring and autumn, respectively.  It’s easy to forget though that just as our northern hemisphere is slowly blooming into spring, the southern hemisphere will be celebrating the autumn harvest.  Another interesting fact:  the sun rises precisely from the east and sets precisely in the west on equinoxes.  

As the days lengthen the average temperature rises and nature is quick to take note.  Trees begin budding and grass shoots and wildflowers begin poking through the last of the slush.  Before too long insects are hatching, the birds are returning and larger wildlife are migrating out of their wintering grounds.  The number of daylight hours keeps on increasing until the summer solstice, the longest day of the year, which is on June 21st this year.  The days then gradually get shorter through the autumnal equinox, up to the winter solstice on December 21, 2014. 

In Missoula, there is still a chill in the air and ice on the Clark Fork River’s banks.  But thanks to the passing of the equinox, summer’s warmth really can’t be too far off.

09 February 2014

Outdoor Explorations: Rattlesnake Ski Day

Winter has returned to western Montana, and we snow-lovers are thrilled. To many of us, to wake up to 6" of new, fluffy snow means one thing on a fine weekend day: we have to get out into it.  My husband and I donned our layers and, armed with chocolate, water, a thermos of tea, and several eggy-avocado-y burritos, headed up to the Rattlesnake Recreation Area, where the parking lot was almost full and the snow was still falling. Two weeks ago the main trail was a sheet of ice, only ideal if one's goal was broken bones or bruises . . . but a foot of snow later, all is transformed.

photo by Allison De Jong

photo by Allison De Jong

photo by Allison De Jong

photo by Allison De Jong

photo by Allison De Jong

photo by Allison De Jong

What are your favorite winter activities?  Where do you love to go to see wintry beauty at its finest?

07 February 2014

Friday Field Notes: Winter Gemütlichkeit

Photo: Ryan Milling
Now that Montana is back into the throes of Winter, I can postpone my pining for spring and enjoy the winter wonderland. I have not been able to look outside without being reminded of the things I truly love about the Northern Hemisphere being tilted away from the sun.

Snow is probably number 2 on my list of enjoyable frozen things (number 1, of course, occupied by ice cream). Snow affords us fantastic opportunities to enjoy nature. Skiing, sledding, snowshoeing, frolicking, track identifying, snowflake admiring...

The list goes on.

I usually like to share my experiences in wild snowy places and I always experience a distinct emotion that I feel the English language has no single word to describe. The Germans must have spent some serious time in the snowy Black Forest or Alps with their friends and loved ones to come up with this word: Gemütlichkeit. The word describes a sense of kinship and coziness but also a feeling of unhurriedness and sense of place.

I wonder if my feeling of Gemütlichkeit this time of year is attributable to something intrinsic in snow. The birth of a snowflake takes place far above tree limbs and rooftops, their final resting places. Snowflakes form when cold water droplets crystallize around particles of pollen or dust in the atmosphere. As the ice crystals descend toward our sidewalks and ski slopes water vapor in the air crystallizes around them, forming familiar six-sided snowflakes.

The old adage goes "no two snowflakes are alike"--and that's pretty much true! The length of each arm of a snowflake is determined by its immediate environmental conditions (mainly temperature and moisture in the air: warmer/wetter = longer spindly flakes, colder/drier = shorter, more plate-like flakes). Each snowflake has minute differences in its immediate environment and so each one branches at a different point, or grows a different length, etc.
6-fold symmetry of ice crystals.

Snowflakes get their distinct 6-fold symmetry from the molecular structure of ice crystals, which is also a 6-fold symmetry. The ice crystals build on each other until the snowflake itself mirrors its molecular structure.

I suppose ultimately each individual snowflake is a collection (maybe even a companionship) of ice crystals, making a journey together towards the earth, and landing in just the right places for us to enjoy.

Photo: Ryan Milling

31 January 2014

Friday Field Notes: Chinook Winds of Fortune

On my ride into the Montana Natural History Center this morning there was one thing that was impossible not to think about: WIND. Struggling against a current of wind on an icy bike path is no cakewalk. Missoula doesn't get this windy too often, but just a handful of miles across the Continental Divide onto Montana's high plains, it's another story.

Most of Montana is occupied by rolling grasslands, once dominated by bison, pronghorn, and prairie dogs. Beautiful shortgrass prairie stretched from the flanks of the Rockies and moated the island ranges of the central and eastern parts of the state. The rich soils that sustained the plentiful life were also ideally suited for growing crops like wheat and alfalfa and stock grazing. A short time after the advent of white settlers, much of the prairie had been checkered with farms and fences, altering the pristine landscape into an anthropomorphized version of its former self.

Looking out from Square Butte towards the Missouri River Breaks
Weather, however, remains indifferent to our terrestrial tillings, not appearing to care about our comfort or chapped faces.

Wind has played an important role in Montana's history, particularly on the eastern slope of the Rockies. From harnessing wind for energy production, to dispersal of seeds and pollen for various plants, wind, despite its indifference, is critical for life on the prairie.

Chinook winds have certainly made their mark on Montana history. A Chinook wind a is warm, dry air mass that rips down the east slope of high mountains and warms the plains it crosses. Chinooks form from  westerly humid cells of air from the Pacific that dump their moisture on the west sides of mountain ranges (the great and mighty Rockies in our case), then warm adiabatically on their way back down the eastern side. The Chinook winds reach temperatures up to 60 degrees F and tear across that landscape at speeds up to 100 mph, melting and sublimating snow in their wake.
These winds are most common and severe from Cutbank to Helena, Montana. The high, steep eastern slopes of Glacier and the Bob Marshall and Scapegoat Wildernesses warm more quickly. The greatest temperature change in a 24-hour period in the U.S. was due to a Chinook wind, and occurred in Loma, Montana. The temperature went from -54 to 49 F, a 103-degree change! It is plain to see that ranchers would have relied on these remarkable weather events to make it through the unforgiving winters that punctuate every year in central Montana.

Waiting for a Chinook by Charlie Russell
As I bike back home today against that not-so-warm wind coming out of the mouth of Hellgate Canyon, I'll be dreaming of warm, dry Chinooks on the prairie.

30 January 2014

Nature Notes: Tracking in the Seeley Lake Region

Oh, Animal Tracks
Left in the Snow
You provide a Story 
that I so long to know.

But with time and patience
I can follow each track
leading me to find you
at the back of the pack.

24 January 2014

Friday Field Notes: Icy Sentinels: Stalwart Herons in Winter

Riding my bike in the summer along the Clark Fork River sometimes feels like an exhibition of nature. Munching beavers, darting kingfishers, and watchful Osprey are rarely out of sight or unheard. Trout break the surface of the river and grebes and their allies dip to catch a morsel under the cool water. But, as the warm clear mornings start to turn into cold ones and ice forms along the river's bank, only the hardiest animals show themselves.

A watchful eye in winter will turn up some of these unyielding creatures. One not too hard to spot is the Great Blue Heron. I was amazed to see that these large graceful birds were waiting at the edge of the ice, staring motionless into the water, as if mesmerized by the chunks of ice floating by. My thoughts then turned to a poem by renowned poet Mary Oliver--Herons in Winter in the Frozen Marsh.


This poem captured much of the feeling I experience while watching these icy sentinels.

If you look carefully at some places on the river ice you can see their "pitchfork" footprints along the water's edge. You may be wondering how the herons can stand the cold with their long scaly legs in the frigid water or on the ice, and the answer is that they are equipped with a special routing of blood vessels in which the vessel carrying blood out to the leg lies directly against the vessel carrying blood back in. This is called "counter-current heat exchange," and is an adaptation used by many organisms across the globe. The blood going into the legs warms up the blood coming back into the body, keeping the heron's body temperature at a remarkable 103 to 106 degrees Fahrenheit (keep in mind that the average human body temperature is 98-99 degrees Fahrenheit). This allows them to stand at or in the water's edge and watch for fish and crustaceans for long periods of time.

As for me, I feel fortunate that I don't have to stand barefoot in the cold river to catch a bite to eat. I'm content just watching the pros at work.

So next time you find yourself along the river, make sure to scan for herons, motionless and cold, looking for lunch.