Fountains of Youth – Classic trout flies that have withstood the test of time … flies that remain “forever young”

by Rusty Dunn

On a cloudy cool day in April, you arrive onstream to find blue-winged olives in the air and on the water.  Fish rise steadily below each riffle.  Jackpot!  You tie on a size #16 BWO dry fly and stealthily approach the first pool.  You cast to a riser, and a nice trout ascends from the depths, approaches your fly, but turns away at the last moment and descends into the pool.  Another cast, same result.  You’ve just suf­fered a fly angler’s classic indignity.  The trout refused your perfect presentation.  A proverbial slap in the face.  Not to worry.  You’ve read all about the situ­ation and know exactly what to do: switch to a smaller version of the same fly.  You remove the size #16 and tie on a #18.  A few more casts, and another nice trout rises from the depths.  Another look, another slap in the face.  You’re thinking, “These BWOs must be smaller than I thought”.  You clip off the size #18 and tie on a #20.  More refusals.  In despera­tion, you try a size #22.  Not even a look.  You switch to a different BWO dry and repeat the progression.  You catch a few trout but, despite all the fly swapping, feel that you missed out on a bonanza.  The hatch wanes, and you walk away think­ing, “What did I do wrong?”.

You were probably mere inches away from success!  Hatch­ing mayfly nymphs ascend from the stream bot­tom and accumulate just under the surface, where they transition to aerial adults.  The process of transition is quite lengthy, and trout feed heavily on the intermediate stages.  We collectively call these stages “emergers”, a term that was first used in the literature in two influential 1971 books (Selective Trout by Swisher & Richards and Hatches by Caucci & Nastasi).  The concept of insects physically transitioning at the sur­face from nymphs to adults, how­ever, is ancient.  William Blacker accurately described the process in 1842 (Blacker’s Art of Fly Mak­ing), and his Winged Larva is arguably the very first fly that unambigu­ously imitates what we today would call an emerger.  Hundreds of authors since Blacker have em­pha­sized the importance of emergers and designed thou­sands of flies to imitate stages of an emer­gence.

Trout feeding on emergers – even those under the sur­face – usually produce a visible disturbance (a “rise”) on the surface.  As described by the legendary F.M. Halford in Dry Fly Fishing in Theory and Practice (1889),

“The apparent rises are bulges, and instead of sucking in the duns when hatched, the fish are busily engaged in chasing and securing the Ephemeridae in the nymph state, before they have emerged from the shuck“.

Experienced anglers recognize bulging rises vs. sur­face rises and act accordingly with their imitations.

Mayfly emergence is an untidy process involving sus­tained quivering motions as the winged adult struggles to escape its shuck, pierce the surface film, and extend its wings, legs, etc.  Generations of talented anglers have struggled to imitate emergers.  George Marryat, a famous contemporary of Halford, described the frustra­tion of fly choice when trout are bulging: “You can imi­tate the nymph, but you cannot imitate the wiggle”. 

Au Contraire!  Wet-fly practitioners dating to the earli­est of times showed the way.  Wingless wets, winged wets, fuzzy nymphs, and ragged flies tied of soft water absor­bent materials imitate nymphs and emerg­ers quite well.  Their soft flowing fibers of fur and feather quiver with every little puff of current.  The key is to fish such flies just under the surface, where they imi­tate strug­gling emergers.  Soft feathery flies also imitate failed hatches, in which drowned naturals drift near the surface as dishev­eled tangles of body parts.

Englishman G.E.M. Skues was a master of nymphing near the surface with soft-hackled flies.  He popular­ized the methods worldwide, and his book The Way of a Trout With a Fly (1921) is a landmark in the history of fly angling.  This year marks its 100^th anniversary.  The book describes trout behavior, and it remains fresh and relevant today a century later.  Skues’ Medium Olive Nymph is an excellent emerger imitation during a BWO hatch.  Fish it trailed behind an indicator dry (e.g., para­chute BWO) and allow the nymph to sink an inch or two below the surface.  Be ready for that bulg­ing rise, only this time you will know what to expect and likely be hooked up on a beautiful trout.

Copyright 2023, Rusty Dunn

Medium Olive Nymph 

Skues greatly enjoyed olive hatches, and his writings describe well over a dozen different imita­tions keyed for use in differing months.  This Medium Olive Nymph pat­tern for the early season was published in Side-Lines, Side-Lights & Reflections (1932).