The abundant tiger swallowtail butterflies that came out early this summer endured the winter dormant in their chrysalises. Their caterpillars eat cottonwood and aspen leaves.

Photo by Tom Ross

The abundant tiger swallowtail butterflies that came out early this summer endured the winter dormant in their chrysalises. Their caterpillars eat cottonwood and aspen leaves.

Tom Ross: Butterfly sightings abound

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Tom Ross

Tom Ross' column appears in Steamboat Today. Contact him at 970-871-4205 or tross@SteamboatToday.com.

Find more columns by Tom here.

— Looking on the bight side, if there’s anything good about beginning summer in a severe drought, it could be that mosquitoes are difficult to find at a time when they are usually peaking at valley elevation.

I might have sustained one mosquito bite while fishing along the Yampa River.

I know that they are present in the high country this week, but the continuing bouts of gusty wind have blown many of them to Nebraska, never to buzz around our heads again. Even in the high country this year, I predict that the skeeters’ reign will be a brief one.

On the other side of the six-legged bug ledger, unless I’m imagining things, the beautiful tiger swallowtail butterflies are in unusual abundance. I’m seeing them everywhere, sometimes even in pairs that flirt in a spiral dance about nine feet off the ground. The large yellow butterflies are busy gathering nectar from almost any available flower, but particularly the lilac bushes that bloom later into summer here than any place that I know in the Midwest.

Western tiger swallowtails, mostly yellow with black stripes and spots of deep indigo on their wings, probably are the largest butterflies to be found in the Rocky Mountain states — with a wingspan as wide as four inches.

There might be a couple of reasons why we’re seeing large numbers of these flashy insects this month. Their caterpillars like to eat cottonwood and aspen leaves and that food source appeared in abundance earlier than usual this spring.

Tiger swallowtails deserve some respect for the ability to survive our long winters. For tiger swallowtail caterpillars that emerge early in the summer, it only takes a month once they wrap themselves in their chrysalis to make the transformation from caterpillar to winged adult. Other tiger swallowtails, hatched in late summer, are forced to hang around all winter. They are able to go dormant and survive in the chrysalis through our typically long, deep winters.

Those tiger swallowtails get an early start in spring (even earlier than usual this year) and once they spread their wings, they head straight for a mud puddle where they can soak up water and minerals. You have to admire their ability to endure our winters.

I’ll always feel a strange, little connection to tiger swallowtails, as I went through a period in my childhood when I collected them and displayed them on mounting boards as entomologists do.

When I was about 10 years old, my father, a military reservist, was assigned to spend two weeks of the summer at the Pentagon, and our family tagged along. I caught the first tiger swallowtail of my career as a lepidopterist during a visit to the National Zoo. As I was enlisted to carry my little sister’s folded up baby stroller later in the day during a tour of the White House, I entrusted my prize catch to my mother’s purse. Naturally, its wings became shredded amongst the combs and lipstick tubes, and I was devastated.

I no longer feel the urge to capture butterflies in a net, but that long-ago memory always returns every time I get the chance to photograph a tiger swallowtail on a colorful blossom.

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