Rocky Mountain High - Part 3

[Mark Walker]

On Monday, July 22, my family and I ventured northeast of Gunnison, Colorado
to drive over the spectacular Cottonwood Pass - elevation, 12,136 ft.  The
road surface turns quickly into dirt - but it is well grated and makes for
easy driving.  This is one of the biggest differences between the Rocky
Mountains and the High Sierra Nevada Mountains I've enjoyed for a lifetime
in California.  In Colorado they've grated jeep trails to many of the
highest elevations.  In the Sierra's, there are only a few roads that
penetrate the highest elevations - and these are principally limited to low
mountain passes.  I suspect that one of the major reasons for this was the
mining boom that occurred in much of Colorado during the last part of the
19th century.  Precious stones and minerals have a way of convincing people
to build roads where they would otherwise be content with primitive walking
trails.
 
We arrived at the pass at 10:30 a.m., and found the barren peaks highlighted
with much sunlight.  The temperature, which had been well into the 90's
since leaving southern California, was now dipping below 60 degrees F.
There was also a good strong wind blowing.  Nevertheless, we decided to hop
out and search a few of the high mountain meadows for butterflies.  We found
the meadows damp and full of flowers, and as we walked softly along we began
seeing our first Colias meadii (Mead's Sulphur) zipping out from below the
arctic meadow tufts. This butterfly reminded me of the sierran Colias
behrii, both incredibly green below and having the tendancy to disappear
after erratically alighting in the meadow grass.  Unlike Behr's, however,
Mead's Sulphur has a stunning orange dorsal color.  They are so orange, in
fact, that it is easy to mistake them for Speyeria or Boloria upon first
sighting.  These sulphurs, along with many of the other species we would
find, would tend to fly great distances after being spooked from their
resting spots.  This, coupled with the steep, uneven terrain and general
lack of oxygen made it particularly difficult to pursue them en chase.  We
(my son was the only one who was willing to venture with me into the alpine
wilderness) had less than a 10% success rate.  We coined a new name - the
Misty Mountain Flop - for the resulting acrobatics.  Every now and then
something totally new would emerge from the tundra flora and we would find
ourselves in an accelerating downhill sprint - only to end with empty net
and suffering from severe hyperventilation.  It can be particularly hard to
suck air at 12,000 ft.
 
Another interesting phenomenon occurs in this habitat.  Arctic Lepidoptera
seem to be well equipped for falling at a whim and disappearing into the
darkest depths of the arctic meadow landscape.  I managed to trap one
freshly emerged Boloria eunomia (Bog Fritillary) against it's perch with my
net, only to discover that the insect had completely disappeared.  Even
after much combing of the stunted undergrowth, I still was unable to locate
this butterfly.  Amazing.  While butterflies from other habitats are quick
to leap up and out of the way, these bugs seem to know that their best
chances of escape are to fall limp and to fall down.  It's effective, that's
for sure.  It leaves the amateur butterfly hunter scratching its head.  I
spent a lot of time scratching.
 
After only an hour or so, the weather maker that is the Continental Divide
reared it's spectacular head once again.  In just a matter of minutes, the
whole area was consumed by a thunderhead which grew before our very eyes.
And in ten minutes, the hail began.  Good sized hailstones (on the order of
5 mm in diameter) rained down upon us, stinging our flesh.  We made a mad
dash for the vehicle, and then sat and admired the animated storm from
within the confines of our rental vehicle.
 
That would be the end of our butterflying for the day.  One hour at 12,000
ft. and then it was over.  It seemed a shame to drive so far for just an
hour.  But then we realized that the bugs and habitat that we had just
experienced, as well as the calisthenics they demanded, made it all easily
worthwhile.
 
Our list:
 
Parnassius smintheus (Rocky Mountain Parnassian)
 
Colias meadii (Mead's Sulphur)
Colias scudderi (Scudder's Sulphur)
 
Lycaena nivalis (Nivalis Copper)
Plebejus saepiolus (Greenish Blue)
Plebejus icarioides (Boisduval's Blue)
Agriades glandon (Arctic Blue)
 
Speyeria mormonia (Mormon Fritillary)
Boloria eunomia (Bog Fritillary)
Boloria chariclea (Arctic Fritillary)
Phyciodes pratensis (Field Crescentspot)
 
Erebia epipsodea (Common Alpine)
Erebia callias (Colorado Alpine)
 
Mark Walker
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.yale.edu/mailman/private/leps-l/attachments/20020805/4a9a241c/attachment.html