Sparkle Dun
Craig Mathews' emerger design sits in the film with a trailing Antron shuck, imitating a mayfly emerging from its nymphal shuck. Essential during PMD and BWO hatches when trout key on vulnerable emergers. The Sparkle Dun is one of the most important patterns to come out of the Yellowstone country fly fishing tradition. Craig Mathews designed it to fill the gap between a fully submerged emerger and a high-riding dun pattern. The result is a fly that sits in the surface film with a deer hair wing extending upward and a trailing Antron shuck dragging in the water behind, precisely imitating a mayfly that has broken through the surface and is shedding its nymphal exoskeleton. This is the moment when mayflies are most vulnerable, and it is the moment when trout feed most selectively. The Sparkle Dun has earned its place as a must-carry pattern on Montana's premier hatch-matching rivers. During PMD hatches on the Missouri and upper Madison, trout often ignore fully emerged duns in favor of the crippled and emerging insects caught in the film. The Sparkle Dun matches this stage perfectly. During BWO hatches in spring and fall, a size #18-20 olive Sparkle Dun can be the only pattern that produces when trout are locked into their feeding rhythm and refusing everything else.
Pattern Details
- Type
- Emerger
- Seasons
- spring, summer, fall
- Hook Sizes
- #14-20
- Hook Type
- Standard dry fly hook
- Tying Difficulty
- Intermediate
- Imitates
- Emerging mayfly duns (Pale Morning Duns, Blue-Winged Olives, and other Ephemeroptera)
Recipe & Materials
- Hook
- TMC 100, sizes 14-20Shop
- Thread
- 8/0, color to match body
- Trailing Shuck
- Amber or brown Antron yarn
- Body
- Superfine dubbing, PMD yellow-olive or BWO olive-gray
- Wing
- Coastal deer hair, natural, fanned 180 degrees
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Technique & Presentation
Fish the Sparkle Dun on a dead drift with no drag. This is a pattern that demands perfect presentation; if the fly drags even slightly, selective trout will refuse it instantly. Use a reach cast, pile cast, or S-curve cast to achieve the longest possible drag-free drift. Position yourself to present the fly from an angle that minimizes cross-current drag.
The Sparkle Dun should ride in the surface film with the body partially submerged. Do not apply floatant to the body or shuck; only the deer hair wing should be treated. This allows the fly to sit at the correct depth, with the Antron shuck trailing in the water as a trigger for trout that are keying on emerging insects.
During a heavy hatch, selectivity becomes extreme. Watch rising trout carefully to determine whether they are eating duns, emergers, or spinners. If you see gentle, rhythmic rises that leave small bubbles, the fish are likely eating emergers, and that is your cue for the Sparkle Dun. Cast 2-3 feet above the fish and let the fly drift naturally through the feeding window. Be ready for a subtle take; the fish may simply open its mouth and let the current carry the fly in.
History & Origin
The Sparkle Dun was created by Craig Mathews and John Juracek, the innovative duo behind Blue Ribbon Flies in West Yellowstone, Montana. The pattern was developed in the late 1980s and published in their influential book 'Fishing Yellowstone Hatches' in 1992. Mathews and Juracek spent years studying trout feeding behavior in Yellowstone National Park's rivers and spring creeks, observing that trout preferentially selected emerging mayflies over fully emerged duns.
The Sparkle Dun's design was groundbreaking in its combination of a Comparadun-style deer hair wing with a trailing Antron shuck. The shuck was the key innovation; it represented the nymphal exoskeleton that an emerging mayfly drags behind it as it breaks through the surface film. This element transformed the fly from a simple dun imitation into a true emerger pattern. The Sparkle Dun has since become one of the most widely imitated designs in fly tying, inspiring countless shuck-trailing emerger patterns.
Where to Fish This Fly
Madison River
Southwest Montana
During PMD emergence
Missouri River
Central Montana
PMD emerger variation
Bighorn River
Southeast Montana
Emerger during PMD hatches
Colorado River
Grand County / Northern Mountains
Matches the signature PMD hatch from late June through August
South Platte River
Front Range / South Park
Sparkle Dun for PMD hatches in Cheesman Canyon
Bighorn River (Wyoming)
North Central Wyoming
Sparkle Dun during PMD emergence
Henry's Fork
Eastern Idaho
Sparkle Dun for Flavs and PMD emergers on the Ranch
Silver Creek
Central Idaho / Sun Valley
Sparkle Dun for PMD and Callibaetis emergers
Crooked River
Central Oregon
Best dry fly during PMD hatches May through July. Sparkle Dun #16-18.
Metolius River
Central Oregon (Cascades)
Sparkle Dun during Green Drake hatch in fall
Owyhee River
Southeastern Oregon
Sparkle Dun during PMD emergence
Yakima River
Central Washington
THE fly for March Brown hatches, Sparkle Dun in tan/olive #10-14
East Walker River
Eastern Sierra / Mono County
PMD Sparkle Dun for summer hatches
East Walker River
Western Nevada / Lyon County
#1 summer pattern for PMD hatch; sizes 16-18
Upper Kennebec River
Western Maine / Somerset County
Sparkle Dun in size 12-14 during Hendrickson hatches in May.
West Branch Penobscot River
North-Central Maine / Piscataquis County
Sparkle Dun in sizes 12-14 during Hendrickson hatches.
Rapid River
Western Maine / Oxford County
Sparkle Dun in sizes 12-14 during Hendrickson hatches.
Magalloway River
Western Maine / Oxford County
Sparkle Dun in sizes 12-14 during Hendrickson hatches in May.
Roach River
North-Central Maine / Piscataquis County
Sparkle Dun in sizes 12-14 during Hendrickson hatches.
Grand Lake Stream
Downeast Maine / Washington County
Sparkle Dun in sizes 12-14 during Hendrickson hatches in May.
Crooked River
Southern Maine / Cumberland and Oxford Counties
Sparkle Dun in sizes 12-14 during May Hendrickson hatches.
East Outlet of the Kennebec River
North-Central Maine / Piscataquis County
Sparkle Dun in sizes 12-14 during Hendrickson hatches.
Saco River
Mount Washington Valley / Carroll County
Sparkle Dun essential for Hendrickson hatch, the best mayfly emergence of the year. Size 12-14.
Baker River
White Mountains / Grafton County
Sparkle Dun for Sulphur hatches in June-July. Size 14-16.
Related Emerger Patterns
RS2
Rim Chung's elegant emerger pattern imitates Baetis and midge emergers in the surface film. The RS2 is a year-round producer on the Missouri and Bighorn, where technical anglers target rising fish during midge and BWO hatches. The RS2, short for 'Rim's Semblance 2', is one of the most elegant and effective emerger patterns ever designed. Its sparse design features a beaver fur or Antron body, a split Micro Fibett tail, and a puff of CDC or web-like wing material that suggests the unfolding wings of an emerging mayfly or midge. The pattern sits in the surface film with its body submerged and its wing material visible above, creating a perfect silhouette of an insect caught in the act of hatching. On Montana's tailwater rivers, the RS2 is an essential pattern for technical dry fly and emerger fishing. During the prolific BWO and midge hatches on the Missouri and Bighorn rivers, trout often key on emergers trapped in the surface film rather than fully emerged adults. When you see trout rising with subtle, sipping rises but they refuse your dry flies, the RS2 is the answer. Fish it on 6X or 7X tippet with a drag-free drift, and prepare for the satisfaction of fooling highly selective tailwater trout on one of fly fishing's most refined patterns.
BWO Emerger
A Blue-Winged Olive emerger pattern with a slender olive body and CDC wing. BWO emergers are critical during spring and fall Baetis hatches, particularly on overcast days when these tiny mayflies hatch in incredible numbers. The Blue-Winged Olive hatch is one of the most important and consistent hatches on Montana's rivers, occurring reliably in spring and fall when overcast skies and cool temperatures trigger mass emergences of Baetis mayflies. During these hatches, trout feed with extraordinary selectivity, often refusing adult dun patterns in favor of the emerging insects trapped in the surface film. The BWO Emerger, with its slim olive body and CDC wing, is specifically designed for this scenario. The pattern's design places it right in the feeding zone that matters: the surface film. The CDC wing provides just enough buoyancy to keep the fly suspended at the meniscus while the slender olive body hangs below, mimicking a Baetis nymph in the act of emerging. CDC (cul de canard) feathers are the ideal material for this application because their natural oils repel water without artificial treatment, and their soft, web-like structure provides a lifelike impression of unfolding wings. On the Missouri, Bighorn, and spring creeks throughout Montana, this pattern is essential equipment during every BWO hatch.
CDC Caddis Emerger
A soft-hackle style caddis emerger using CDC feathers for buoyancy and movement. Fish it in the film or just below during caddis hatches. The natural oils in CDC create a lifelike shimmer that trout find irresistible. The CDC Caddis Emerger bridges the gap between traditional soft-hackle wet flies and modern surface emerger patterns. Using CDC (cul de canard) feathers as the primary wing and hackle material, this pattern sits in or just below the surface film, perfectly imitating a caddis pupa ascending to the surface and beginning to shed its pupal shuck. The CDC fibers trap tiny air bubbles that give the fly a lifelike, shimmering quality, mimicking the gas bubble that natural caddis pupae use to propel themselves to the surface. On Montana's rivers, caddis emergers fill a critical niche during the prolific caddis hatches that occur from spring through fall. When trout are splashing at the surface during a caddis hatch but refusing adult patterns, they are often feeding on emerging pupae just below the film. The CDC Caddis Emerger presented in or just under the surface film is the solution. It is particularly effective on the Yellowstone during the Mother's Day caddis hatch, on the Madison during summer evening emergences, and on the Gallatin where caddis are a primary food source throughout the season.
Blue-Winged Olive CDC Emerger
The Blue-Winged Olive CDC Emerger is a deadly pattern designed to imitate the vulnerable transitional stage when Baetis mayflies are emerging from their nymphal shuck and breaking through the surface film. This critical moment in the mayfly lifecycle represents one of the most productive feeding opportunities for trout, and patterns that effectively mimic this stage often outperform both standard dry flies and subsurface nymphs during active hatches. Cul de Canard (CDC) feathers are the secret to this pattern's effectiveness. These unique feathers, taken from around a duck's preen gland, contain natural oils that make them extraordinarily buoyant and water-resistant. CDC creates a lifelike, translucent appearance in the surface film that perfectly mimics the wings of an emerging mayfly. The soft, mobile fibers also create subtle movement with even the slightest current, triggering strikes from selective trout. The BWO CDC Emerger excels during the peak of Blue-Winged Olive hatches, particularly when trout are feeding just subsurface on emerging nymphs rather than taking fully emerged duns. This often occurs during the initial stages of a hatch or in turbulent water where emergers struggle to break free from the surface. The pattern sits partially in and partially above the surface film, presenting a silhouette that trout find irresistible. Fishing this pattern requires delicate presentations with fine tippets (6X-7X) and careful attention to drag. The CDC emerger should be allowed to drift naturally without any tension on the leader. Strikes can be subtle—often just a slight hesitation in the fly's drift or a small dimple on the surface. During heavy BWO emergences on spring creeks and tailwaters from Oregon to Pennsylvania, this pattern can produce extraordinary results when nothing else works on ultra-selective trout.
Blue-Winged Olive Emerger
The Blue-Winged Olive Emerger is a versatile transitional pattern that bridges the gap between subsurface nymph and fully emerged dry fly. Designed to sit in or just below the surface film, this pattern imitates the critical moment when Baetis mayflies are transforming from nymphs to winged adults—a period of extreme vulnerability that trout exploit with focused feeding. What makes emerger patterns so effective is that they match the behavior trout actually observe during hatches. Research has shown that trout often feed more heavily on emergers than on either nymphs or fully emerged duns, particularly in smooth water where they can selectively target insects trapped in the surface tension. The BWO Emerger presents the segmented body of the nymph combined with the emerging wings, creating a silhouette that trout recognize instantly. This pattern excels during all phases of Blue-Winged Olive emergences, which occur throughout much of the year but peak in spring and fall. It's particularly effective during the middle stages of a hatch when the majority of insects are transitioning, and when weather conditions (cold, wind, or rain) slow the emergence process, causing insects to struggle in the film longer than usual. These are precisely the conditions when BWO hatches are most likely to occur. The BWO Emerger works across diverse water types—from the spring creeks of Pennsylvania to the tailwaters of Colorado and Wyoming. It can be fished alone on a fine tippet with careful presentations, or as a dropper below a buoyant dry fly indicator. The pattern's year-round utility makes it essential for anglers who fish technical waters where Baetis hatches provide consistent feeding opportunities even during winter months when other mayflies are absent.
Film Critic Emerger
The Film Critic is a deadly emerger pattern designed to imitate mayflies trapped in the surface film during the vulnerable transition from nymph to adult. Created by Wyoming guide Pat Dorsey, this pattern capitalizes on the fact that emerging mayflies often spend critical seconds suspended in the meniscus while their wings unfurl—a moment when they're helpless and highly visible to feeding trout. The Film Critic's low-floating profile and realistic silhouette make it devastatingly effective during mayfly hatches when trout focus on emergers rather than fully emerged duns. The pattern features a dubbed body that hangs below the surface film, a CDC wing that suggests the partially emerged wings, and a high-visibility foam post that allows anglers to track the fly while maintaining a realistic profile to the fish. This design perfectly mimics the natural emerger's posture in the water, with the nymphal shuck trailing below and emerging wings breaking through the surface. The pattern works for multiple mayfly species by varying size and color, including Green Drakes, Pale Morning Duns, and Blue-Winged Olives. Film Critic excels during selective feeding situations when trout refuse standard dry flies. During heavy hatches, trout often key on emergers because they're easier to capture than fully emerged adults that can fly away. The emerger's helpless position makes it a high-percentage target. This pattern's effectiveness is enhanced by fishing it dead-drift in the surface film, occasionally giving it a slight twitch to imitate the struggling insect. The pattern has proven effective across all Western waters, particularly in technical spring creeks and tailwaters where educated trout scrutinize their food carefully. South Platte River in Colorado, Wyoming's North Platte, Montana's Missouri River, Idaho's Silver Creek, and California's Hat Creek all see excellent Film Critic action. The pattern's versatility across mayfly species and sizes makes it an essential emerger selection for serious trout anglers fishing from spring through fall.