Those practitioners who follow the traditional description of fly fishing understand that insects lie at the core of their sport.
While mayflies are not necessarily the most dominant attractors of trout in terms of numbers, they are easily the most recognizable. With their tall wings and almost magical tendency to appear suddenly on the water, these tall winged insects have come to symbolize what hatches are largely about both on the Henry’s Fork and worldwide.
Although mayflies occur in a variety of sizes, the average would probably not exceed size 16, and many are considerably smaller. There are times, however, when those on the upper end of the scale cause us to temporarily forget 6X leaders and tippets and squinting to follow a tiny imitation as it drifts on the surface at distances of 30 feet and beyond.
Drake is a term of European origin generally applied to a mayfly larger than size 14, and they are considered royalty by fly fishers wherever they exist.
On the Henry’s Fork, the early summer emergence of Green Drakes is an event targeted by many who will only visit the river at this time of year. Known primarily for something less than hospitable treatment of intruders, Henry’s Fork trout display uncharacteristic charity when Green Drakes begin to dominate their menu beginning in mid-June and usually lasting through early July.
At a solid size 10, Green Drakes can have the ability to sometimes erase the futility of an imperfect cast, minor drag, or an imitation that might otherwise be subject to ridicule.
The perfect habitat for Green Drakes is clean gravel, which often features rippled water that can help to mask a flawed presentation. It can be a different story on slow, shallow currents where insect numbers may be lower but trout resistance can be more typical of what anglers have come to expect on the Henry’s Fork. With this in mind, it is a good policy to carry an assortment of emerger, dun, and spinner patterns at Green Drake time. A dark nymph in the appropriate size is also effective for those who don’t mind fishing a subsurface imitation.
As the name implies, Green Drakes are a deep, almost jade green with bright yellow bands along the abdomen and legs. Wings on the spinner are transparent with distinct, dark veins while the dun and emerger wings are a dark smokey gray.
Be on the water early for a chance at a spinner fall, and expect emergence from late morning until mid-afternoon. Cool, overcast weather can delay the hatch into late afternoon or early evening.
Less known but even slightly larger than their green cousins, are Brown Drakes. With an emergence period that often begins slightly later but occasionally extending deeper into July, Brown Drakes exhibit distinct differences with respect to their appearance and behavior.
Unlike the compact, rather burly profile of Green Drakes, Brown Drakes show a more slender abdomen, and the mottled wings appear more upright. The best imitations emphasize the tannish yellow underbody of the natural, although the duns and spinners look darker when viewed from above.
Normal time for Brown Drake emergence is at dusk and can extend into darkness on a warm evening. Cooler weather can push the hatch time to mid-morning and sometimes early afternoon.
A Brown Drake spinner fall will often overlap with emergence, which dictates close observation to determine which stage is being targeted by individual trout. Emergers and nymphs can also be the target, and the situation can be quite complex when all stages become simultaneously available.
Brown Drakes thrive in slower currents flowing over a silted or fine gravel bottom. Their distribution on the Henry’s Fork is limited mainly to the upper reaches with Harriman East generally considered the lower boundary. The strongest hatches seem to appear in areas of heavy aquatic vegetation, which makes the stretch from Bonefish Flat through Millionaire’s especially productive.
Gray Drakes are slightly smaller than the green or brown varieties but at size 12 are still capable of attracting the largest trout to the surface. Like Green Drakes, they are distributed through the first 50 miles of the Henry’s Fork, which includes the area near St. Anthony.
Gray Drakes find comfort in slower currents where they emerge at the edge of the river. Because emergence can be sporadic and spread over several hours, Gray Drake duns seldom appear in concentrated numbers, which differs from the other two drakes of the Henry’s Fork. A Gray Drake spinner fall can be a different story, however, with periodic mating flights that can put numbers of naturals on the water that are close to overwhelming.
On the lower Henry’s Fork where the population seems strongest, Gray Drake spinners can blanket the water in numbers that cause an imitation to be lost amid a horde of naturals. Fortunately, a Gray Drake spinner fall is typically a more restrained affair with the number of naturals at a level that can be managed with determination and sound fishing techniques.
Morning and late afternoon are good times to fish a gray body dun along the bank while either wading or floating.
A big Rusty Spinner is a reliable choice during a Gray Drake spinner fall that can arrive at dusk or earlier on a cool day.
Gray Drakes are primarily a June and early July hatch at lower elevation but I have fished them into early September above 6,000 feet.
Although drakes provide a relatively small window of opportunity to fish big flies on a stout tippet, some of the largest trout of the year are landed during their respective visits. Large mayflies attract large trout wherever they exist worldwide and as kings of the order, drakes are special.