Idaho: Mouse Flies in the Moonlight


“It will remain a nameless river in a nameless state kept a secret because the fishing is rare and I would regret the night I saw another flashlight reflect off the water.”


 
 

Scott Morrison, Nice Brown

 

“Fishing mouse flies on a full moon is not the easiest, or most productive use of your time.”


 

“Other than to note a strike, Morrison and I do not talk on the river. In some ways, mouse fly fishing resembles elk hunting, where stealth and silence are critical to success.”


 

“When they take, they send a three foot column of water into the silvery night, causing my heart rate to jump fifty beats in less than two seconds.”


 

Brown Trout Habitat

 

It will remain a nameless river in a nameless state kept a secret because the fishing is rare and I would regret the night I saw another flashlight reflect off the water. That is not to say this river is never fished for it is fished all the time when the August sun forms an oblique angle over the slow moving water and the heat shimmers off the desert’s black lava. In the early evening, millions of mayflies and caddis rise to form a shimmering sheet above the water. It is a bounty few fish can resist and when the bright rainbows feed upon rising nymphs and the falling spinners, the ring of their rises next to the bank, in midstream, or along the channels between the thick weed beds, betray both their location and size.

Waiting For The Moon

A decade ago I could float the river for hours and never see another fisherman. I was working as a carpenter then and after a long day spent forming concrete, framing walls and cutting roofs, I relaxed in the orange glow of brilliantly lit sunsets and rising fish, the bawls of cows calling their calves, the distant tsk, tsk, tsk, of wheel lines and the rusty rattles and dusty contrails of pickup trucks breaking the limit on the distant county road.

Once the sun set, the air cooled, the hatch waned and the rise faded, night on the river was a wondrous time filled with darting bats, hooting owls, the distant romances of coyotes and the alarmed quack of mallards startled from the reeds by an opportunistic red fox.

I wish I could claim I discovered the secret of mouse flies. That honor, however, must go to Scott Morrison. It was Morrison, my elk hunting partner, who one pre dawn morning while glassing a distant ridge, described the river beneath a full moon.

His description was prophesy. “I’m not saying we’ll catch a lot of fish,” he whispered. Left unsaid was the fact that any trout big enough to tackle a mouse would be a fish of truly Biblical proportions.

There are mouse flies…..and then there are MOUSE FLIES. Scott Morrison ties art. He starts by fixing a chamois tail to a #2 Mustad 79580 hook. He then spins a deer hair body, adds chamois ears, silver bead eyes and black whiskers. Morrison’s mice are almost too good to risk losing to the willows that overhang the river. So good, in fact, that once, during a dinner party, I told the wives of close friends that the only way to catch really big fish, was to use mice.

“Mice?” they inquired with a certain, fascinated revulsion.

I described how, by turning a dozen live mice lose in a fruit dehydrator and dialing it to high, you produced perfectly dead, perfectly dried bait which you could then tie to a hook. To prove how well the system worked, I produced a fly box with three of Morrison’s mice. My audiences’ shrieks quickly grew in volume and violence when I tried to get them to “just touch one!” I discovered that by moving the box to the right or left, I could herd them around the living room. The only part I can’t remember is if I ever told them it was just a joke.

Fishing mouse flies on a full moon is not the easiest, or most productive use of your time. A full moon rises late and does not reach its full strength until midnight. Slipping my fins into the float tube, I gather my rod, flies, flashlight and insect repellent and duck waddle into the current. What in broad daylight would be merely difficult and precarious becomes dangerous and terrifying beneath the moon’s low silvery light. The river is black with a faint platinum disc shimmering across the water. Hidden obstructions hang beneath the surface and the first step can as easily be into thigh deep mud, or a ten foot hole. A second step will be over the handlebars and into the river’s frigid water. If there is a way to get wet while mouse fly fishing, I’ve tried it. I’ve been lucky to escape with little more than a few icy soakings and burdened by my flyrod, vest, flies and net I scuttle carefully across a basalt boulder and into the river where the float tube settles onto the water and the current begins to push me down stream.

Under ideal conditions a belly boat is a head strong craft, better suited to still lakes than moving rivers. Lacking both prow and stern it is driven into the brushy over hangs where beavers have pruned the willows into sharp spears that can puncture the canvas tube as surely as a broadhead. The downstream side of deep holes also hide hazards. Here, where the gravel bottom rises to a few inches beneath the surface, the tube scuffs to a stop and I am forced to flipper furiously, like a spawning salmon, tail finning through shallow water. When that fails, I rise unsteadily to my feet and stagger down stream.

Before you make your first cast, the moon must be full and high enough in the night sky to silhouette live mice as they tumble out of the wild rye into the current. I do not like to fish the river at night and alone. Too much is left to chance and for that reason and to protect the secret, I do not fish without Morrison. Scott not only ties the best mice, he is a master at fishing them. Then too, by taking two vehicles, we avoid the two mile hike with float tubes back to the truck.

Other than to note a strike, Morrison and I do not talk on the river. In some ways, mouse fly fishing resembles elk hunting, where stealth and silence are critical to success. Stripping line from the reel, I cast the mouse into the grass. The fly hesitates in the stiff yellow rye then, responding to my slight tug on the line, falls onto the surface with an authentic and satisfying “plop”. Though very big Rainbows will take a mouse, I am not fishing for Rainbows. It is the Browns I am after. A twenty pound monster was taken a mile from here. I do not know if I want to hook a fish that large. It’s not that I worry about breaking the rod or burning up the reel. I fear hooking it and getting a glimpse of its massive golden body, its weight and dimensions before the reel runs dry and the fish breaks off.

You must use psychology on the massive fish that hang just beneath the surface, turning a dark intelligent eye on the mouse’s confused attempt to reach shore. The moon is said to affect the blood in the same way it pulls at the tides and I wonder if, while finning beneath the dark over hung bank, Browns feel that same quickening of the blood, that same need to breed and feed. And, if they are indeed fresh water sharks, does injury, or imminent death prompt an attack?

I believe it does and casting the fly into the thick rye grass I let it hang for a moment, then gently pull it free, watching with satisfaction as it lands in the channel of deep, clear water next to the bank. I allow the fly to drift for a few seconds before I twitch the rod tip. A shiver echoes down the line to the mouse. By tugging lightly on the line I cause it to dog paddle in a desperate effort to reach land. It is at this moment when the Browns hit. There is no bump and refusal. When they take, they send a three foot column of water into the silvery night, causing my heart rate to jump fifty beats in less than two seconds.

Evening Rise

The moon is high, the mouse is dry and my presentation is perfect and yet nothing rises between the black weeds that wave sinuously in the current. I do not waste my casts. Instead I drop the mouse in the swift water in front of a point which flows into quiet pool where I wiggle the tip, wait and wiggle it again.

You are never prepared for the strike which comes as an explosive column of water beneath the struggling mouse. There is the loud splash and the tail slap of a big fish, followed by the reel’s startled scream.

The smartest fish dig into weed banks or dive into dead fall where they take a purchase on the tippet and break off. Caught in the open pool this fish strips line off the reel in short shrieks that gradually fade in intensity until a stout hen of perhaps three or four pounds wallows into my flashlight’s yellow pool.

Morrison is across the pool when I twist the hook to set her free. “Any size?” he whispers.

I tell him no, then dry the mouse by casting it in the cool night air and drop it next to the bank. After the hen’s frantic fight, I do not expect a take and am startled by a deep “slurp”. I have a second to ponder the size of a fish that sucks a mouse like a mayfly before the surface recedes into a deep vortex and the reel screams. In the next second, the rod tip bucks into the water and the tippet comes whizzing back like a three pointer rejected by Lebron James.

No fish. No mouse fly. Just a pigtailed piece of leader. Shining my light on the line, I curse my consistent bad luck. I am not inexperienced in these matters. This was no dainty 6X tippet, but six feet of eight pound monofilament improved clinched to Morrison’s mouse. What ever broke it was an equivalent fresh water sperm whale finning through this dark river. How big could it be? Ten pounds? Fifteen? Or bigger–perhaps an older, massive brother to the twenty pound behemoth that succumbed upstream.

Either way I am filled with the “what if” of self loathing. If I had been alert and not day dreaming in the moonlight, I might have lowered the rod at the exact moment the fish turned. Or if the fish itself had been incrementally smaller, I might have fought it to exhaustion.

I feel even more foolish when Morrison comments, “That was one hell of a fish. I’ve never heard one slurp a mouse before.”

We catch two more fish that night and lose two. On balance the evening is a success and when I finally crab stiffly across the basalt boulders at the take out, it is 3:00 am. The moon is now in the west sending shivers of silver light across the moving current. Somewhere in the river, beneath this same moon, a huge brown trout is carrying a mouse sized Ahab in it’s jaw. I give serious thought to pursuing the fish the following night. Would the brown be fooled twice in as many days? Highly unlikely, but if it is a true hunter of mice, and the mice are on the move, there was a chance.

“What would you say to tomorrow night,” I inquire.

Morrison presses the light on his watch. “Let me see, I get three hours of sleep tonight, followed by nine hours of work tomorrow, then dinner…. if I could squeeze in a quick nap….” he replies as we follow the dusty, rutted road out toward the highway where I’ve parked my truck .