Story and photos by WES SMALLING

Star-Tribune staff writer

THERMOPOLIS - The boat drifts at a snail's pace down the river, barely moving in the slow current. The river, smooth as glass but mossy, looks more like a bayou than a Wyoming trout stream. Near the bank where Russian olive branches hang low over the water, the dimple of a rising trout appears along the edge of a floating bed of dark green moss.

Cast after cast of my dry fly fails to get the fish to take it, although the sizable looking trout keeps rising over and over again to sip at the smorgasbord of dead and dying insects floating on the surface. I make a last ditch cast as the boat passes. The fly sinks and swings with the pull of the boat, the bed of moss fluttering as the fish races after the fly. A second later, the fight is on.

To a fly-fishing purist - a real trico man - that fish wouldn't count. That's cheating. But I'll take it.

It's cheating because when you fish the trico "spinner fall," you're supposed to entice the trout to the surface with a motionless drift of your fly, imitating the dead insect it's preying on, called a spent wing.

At places such as Wyoming's Big Horn River, the trico spinner fall can be a traditionalist fly fisher's dream. It's the opportunity to "match the hatch" with a floating dry fly when the river's biggest fish are feeding on the glassy surface beneath white clouds of thousands of mating tricorythodes insects, called tricos for short. The tiny bugs swirl in the air drifting over the water like puffs of smoke during the last minutes of their lives before they fall to the water to die.

And be eaten.

While the hatch of dying bugs is a dream to some, to others it's known as the "white nightmare" of fly-fishing. It can be difficult fishing. Watching huge trout rise again and again only to completely ignore an angler's offering can send even the most patient, mild-mannered fisherman into a mad, cursing fit of rage.

Trico enthusiast John Schwalbe, owner of Wyoming Adventures, a fly-fishing guide service for the Big Horn River in Thermopolis, says that to master the white nightmare - without losing your cool - it helps to be able to make near perfect casts. You need to present your fly each time in a motionless drift right to the trout's snout, timing the arrival of the fly to the fish only when the trout is ready to come up for another bite.

It ain't easy, but it's fun.

The little three-tailed mayflies that hatch in white clouds each morning on the Big Horn are the bread and butter of Schwalbe's guide business.

"It's like clockwork from June 1 to mid-October. It's really the best hatch we have on the river," he says, dropping the drift boat's anchor to stop and cast to a few rising trout near the bank. A longtime trico-man, Schwalbe wrote an article all about the little bugs for the September issue of "Fly Fisherman" magazine.

Most fly fishers know their stoneflies, caddis and bigger mayflies. In music, those would be the Greatest Hits, the Top 40, the mainstream artists. Tricos would be the hip underground. Those bands only the cool people in the know have heard of.

Tricos have a cult following, a small but growing number of fly fishers who travel from river to river just to fish their spinner falls. Many are Schwalbe's clients who come to the Big Horn River. Some other Wyoming streams the trico guys hit in the summertime are the Gray Reef of the North Platte River near Casper and the Upper North Platte near Saratoga. The Saratoga chapter of Trout Unlimited puts on an annual summer trico festival called the "Mate and Die Extravaganza."

The trico spinner fall is an exciting challenge because it brings the river's biggest fish up from their usual home in the depths of the river to feed on the dead and dying bugs that are floating past them by the hundreds, he says.

"You'll look downstream and see what looks like a riffle but it's 20 trout just slurping down bugs on the surface."

They'll scoop up five or six bugs in one swallow, but with so many insects to choose from it's common for a feeding fish to ignore your fly on cast after cast. The satisfaction when one finally hits your fly is what it's all about, Schwalbe says.

We continue on our float and spot six or seven trout lined up in a row gobbling down bugs. Schwalbe drops anchor and we cast. I immediately lose sight of my little white-winged fly among the hundreds of real bugs that look like tiny white dots all over the surface.

White nightmare, indeed. Trying to see which one of those hundreds of white dots is my fly is like trying to find a needle in a stack of needles. With no way to know which rise is a fish taking my bug - not some other bug - I take a guess at the next rise I see and lift the rod sharply to set the hook.

Wrong. My fly rips off the surface with a noisy splash and sails high over my head. All the fish stop rising. They're onto us. I blew it.

"Sorry, man," I say a bit sheepishly.

With the patience of a river guide who's seen that happen a thousand times, Schwalbe smiles, pulls up the anchor and says, "That's trico fishing."

And slowly down the river we drift, on to the next pod of rising fish to give it another shot.

In between several foul-ups and curses, I manage to actually catch a few nice sized trout … without cheating.

Trico basics

Tricorythodes is a small type of mayfly that has three hair's-width tails. It typically hatches in the summer on many western streams, but continues to hatch into mid-October in the warm waters of Wyoming's Big Horn River. The trico lives most of its life underwater as an aquatic nymph until it hatches into a flying adult on the last day of its life.

The males hatch at night, swim to the surface, sprout wings and fly to the bushes where they wait for the females. After sunrise, females begin hatching and in the morning sun they meet in the air to mate. The males die first. Then the females, carrying their eggs on their tails, return to the water to lay them. Then the females die.

The mid-morning peak of the cycle is called the spinner fall by trout anglers. It's when thousands upon thousands of the tiny insects are flying in swirling clouds over the water and just as many are floating on the surface dead or dying. The spinner fall is when trout tend to key in on them the most as a food source, often gobbling them up several bugs at a time in one rise.

Although they appear white when the sunlight hits their wings, up close tricos are black, dark brown or dark olive colored.

One reliable fly pattern is a size 18 Trico Spinner. It's usually tied with black or rust colored thread with a little dubbing of the same color on the body. The wings are tied flat in a "spent wing" style with Antron or other white synthetic fibers. Three micro-fibbets make up the tail.

Float and fish

Wyoming Adventures offers guided fly-fishing float trips on the Big Horn River from Wedding of the Waters, where the Wind River becomes the Big Horn River, downstream through the town of Thermopolis.

To book a trip, call Wyoming Adventures in Thermopolis at (307) 272-6792, go online to www.flyfishbighorn.com or send an e-mail to anglingadv@yahoo.com.