That same day, driving home from Sisters on Highway 20, I had the very same thing happen near the 8-mile post. It was unavoidable, but it still saddened me. Killing animals with my motor vehicle is something I try diligently to avoid, but traveling along at 55 mph on a collision course with a butterfly is not like avoiding a mule deer or elk. I saw and heard it hit the windshield and then in a horror of horrors, it caught under my windshield wiper right in front of my eyes and stuck there all the way home.
About three years (or so) ago these creatures went on a reproductive boom in the countryside around Yosemite National Park in California. It took two years for the phenomena to catch up in the Northwest, and now there are California Tortoiseshells - literally - everywhere in Central Oregon. I don't believe it has anything to do with global warming, because according to what I know, they have been doing this boom-and-bust thing for hundreds of years.
From Klamath Falls to Mt. Hood, uncountable numbers of tortoiseshell caterpillars chomped their way through Ceonothus (snowbrush). One year, I watched them defoliate the snowbrush near OMSI's Cascade Science School in the old Skyliner's cabin near Tumalo Falls. When they went into the chrysalis stage, the Golden Mantle Ground squirrels thought they had died and gone to heaven. They gobbled up the delicious, protein-rich chrysalides by the millions, taking advantage of Nature's cornucopia, probably in the same way prehistory native Oregonians did back in the "Good Old Days."
In spite of the feeding frenzy, millions of survivors took to the wing and spread out all over the Northwest, looking for new territory to exploit. (One of those population booms years ago spread California Tortoiseshells all the way to Vermont!) Then, when winter cold weather sets in, they go in search of safe places to hide.
That's exactly what they are doing, keeping out of the way of butterfly-eaters and the harsh winds, rain and snow of winter. Those of you who keep livestock have probably already spooked one or two while moving hay bales or found them hiding in the milk parlor. I've found them tucked away in the woodshed. It's not easy for butterflies to keep out of harm's way and make it though the winter.
"Why don't they freeze to death?" my caller asked. To me, the answer is in the same league as the miracle of metamorphosis. The reason tortoiseshells (and a few other butterflies and chrysalides) do not freeze to death in winter is that they contain a form of antifreeze in their blood - the colder it is, the better the antifreeze.
It's no wonder that the symbol of hospice is the butterfly. If there is any hope for us after the light of mortal life goes out, it has to be that we will find ourselves in a "better place." That is, we undergo metamorphosis as we travel from this life to the next. I choose to believe that we will.
Inside those chrysalides (and moth cocoons) there is an event going on that I choose to call "the miracle of metamorphose;" a biological process where the caterpillar (larva) breaks down into slimy genetic soup. Then, as temperature and time dictates, a genetic code reforms the slime and goo into the adult insect. Three distinct body parts, legs, mouth parts, breathing and digestive systems, muscles that move wings, incredible eyes and sense organs along with a reproductive system slowly form. And on that special warm day in spring or summer, the adult emerges in all its glory.
Bats also spend the winter hiding in places where the temperature remains around 40 degrees Fahrenheit, but they do not posses antifreeze in their blood like insects. Nevertheless, they wake up about three times each winter to pump oxygen into their blood; however, they do not leave the hibernaculum until spring returns. Butterflies (and my bees) also wake up in winter, perhaps to pump oxygen into their blood as well. So, don't be surprised if you go out on a warm winter day and see a tortoiseshell, mourning cloak butterfly or honeybee go zipping by. It's just the way things are in Nature.