In one of the West's more amazing feats of nature, swarms of millions -- no, make that gazillions -- of insects called caddis flies hatch each spring from the green waters of the Arkansas River, and anglers such as Duncan travel far and wide just to see them.
"This is incredible. They're everywhere," said Duncan, 45, an American Airines pilot based in Fort Smith, Ark., as he laid down his fly rod to flick away another dime-sized bug from under his eyeglasses. "It's one of those things you have to see to believe."
Even in a sport where the lies flow as easily as a spring creek, it's hard to exaggerate the size of this insect hatch. Just how big is it?
"There are so many bugs that you can walk across the water on their backs," said angler Jamie Knight of Morrison.
Though the Arkansas River long has been home to a major population of caddis flies, numbers bulged in recent years when managers of upstream reservoirs agreed to release water in a way that more closely mimics nature -- vast spring flows that scour silt from the stream bottom, followed by lower flows the rest of the year that promote bug-baby growth.
After living in frigid water as a wingless nymph for most of the year, the caddis emerges on the Arkansas just as springtime warms the Rockies. New wings send the fly fluttering above the river, where the caddis has airborne sex for a minute and then falls dead shortly after. Of the 100 or so eggs laid by each female adult caddis, only one or two usually survive to adulthood.
Many caddis become meals for the river's brown trout.
"The browns are exhausted from spawning in the fall and surviving the winter. Then the spring caddis hatch starts coming off the river in clouds," said Doug Krieger, an aquatic biologist at the Colorado Division of Wildlife. "It's not unusual for a 10-inch brown trout to gorge itself on a hundred caddis a day during the hatch."
The hatch starts in Cañon City and rolls further upstream each day as water temperatures rise to 50 degrees. Most years, the hatch eventually travels 60 miles to the head of the canyon in Salida, though the ideal conditions sometimes push the bugs another 25 miles to Buena Vista.
Many anglers were lured to the hatch by stories in national magazines such as Fly Fisherman, which told readers this month, "The mother of all Mother's Day caddis hatches occurs on the Arkansas." Other anglers have known about the bugs a lot longer.
For the past 17 years, fishing buddies Bob Peffer, 72, and John Dee, 80, have been swapping flies and lies on the Arkansas. Last week, they waded out of the river together near Vallie Bridge and complained that the currents were blanketed with too many real caddis for any trout to even see a fake fly on a hook.
Bob: "I'm telling you, it's just a cloud out there."
John: "You can't see more than 50 yards. I'm serious."
Bob: "I turned around to talk to John, and I got a mouthful of bugs."
John: "What he said then you couldn't print in the paper."
Bob: "It's a good thing they don't bite."
John: "They give me the willies. It's the worst when they crawl up your nose."
Bob: "You can't..." Ptooie! Bob spits. "Ugh, another one in my mouth."
John: "When you drive back down the river to Cañon City tonight, I'll guarantee you one thing: You'll be cleaning your windshield. Yes, you will."