Green Drake: Granddaddy of the Drakes

This is how the 1956 edition of Funk & Wagnall's new standard dictionary explains the connection of the term "Drake" to angling in America. Ironically, 1956 was also just about the time I first became acquainted with a hatch that would attain legendary status on the Henry's Fork River in eastern Idaho. At a healthy size 10, the Western Green Drake, or Drunella grandis, is certainly of adequate size to become a candidate for impalement on the hook of a bait fisherman, but its significance to fly fishers is something quite different.

In my earliest days of fly fishing, I did not have the knowledge to put a name on the big, brightly colored mayflies, but I knew that their appearance on the water meant almost instant improvement in my ability to fool fish on a river that, even back then, was not easy. In the decades that followed, other hatches of mostly smaller insects would form a rather extensive list of distinctly appreciated events, but nothing has ever surpassed the anticipation and excitement of Green Drake time.

As an angling term, drake is synonymous with large when used to describe any of three oversized mayfly species that inhabit the Yellowstone region. But size is nearly the only physical similarity among the respective hatches designated by color.

For example, the compact and portly profile of any stage of the Western Green Drake contrasts distinctly with the more slender appearance of Brown Drakes and Gray Drakes. Likewise, behavioral differences set the Green Drake apart, as do its habitat requirements. It should also be noted that the Western Green Drake is not related to the Eastern Green Drake, and few similarities are shared between the two. Additionally, there are several subspecies of Western Green Drake that differ slightly in coloration and are found at varying elevations.

Green Drakes are distributed through much of the Western U.S.—from Mexico to Alaska and from Colorado to California. Cool water with medium to fast current and a clean gravel bottom makes ideal habitat for the nymphs, but good numbers of them are also common in the slower, weedy sections of the Henry's Fork and other waters in and near the Yellowstone region.

The annual timing of most aquatic hatches is largely dictated by elevation, and Green Drakes are no exception. On the lower Henry's Fork for example, at an elevation of about 5,000 feet, the air and water temperatures can become ideal for the Green Drake emergence in late May. In Island Park, 30 miles away and about 1,500 feet higher in elevation, the catch-and-release water sees the big bugs within a few days of June 15. It can be early to mid-July before the hatch shows up in Yellowstone National Park, where summer can be pitifully short.

The daily timing of a Green Drake emergence can vary from late morning to midafternoon depending on weather conditions, which can vary considerably in the high country. On a cold, cloudy day, the hatch can be an evening affair beginning as late as 5 P.M. and sometimes lasting until dark.

Because of the nutritional bulk of the insects, a Green Drake Nymph fished at any time during the emergence period is likely to gain attention. Sight nymphing in water where you see subsurface feeding activity is an exciting way to bring visual connection to the process of locating, approaching, and casting to a fish that can elevate the heart rate to a dangerous level. Fortunately, a weighted size 10 imitation can usually be fished effectively on a 4X tippet for aggressive trout sometimes made careless by the prospect of a large food item.

Polarized glasses are an asset in penetrating the glare when working cautiously upstream in search of underwater treasure. An elevated position helps to extend the range at which you can locate a subsurface object, but you must exercise careful movement to avoid spooking the fish.

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A dead-drift presentation with little or no added motion will duplicate the behavior of Green Drake nymphs, which are not active swimmers.

Systematically fishing a nymph in defined holding water can be worthwhile when surface activity is absent, and water conditions do not accommodate sight nymphing. During the Green Drake emergence period, the trout seem more aggressive, and willing to move farther than usual to intercept larger food items. This tendency brings more efficiency to blind fishing a Green Drake Nymph because the fly can drift several feet away from the fish and still be consumed. Fished independently or beneath an indicator, a heavy imitation of the dark nymphs can be equally productive in deeper runs while wading or working the edges from a drift boat.

We all prefer to fish dry flies during a hatch, but there is no assurance that all trout are actually feeding on the surface while a mayfly emergence is underway. Like other mayfly species, Green Drake nymphs rise from the bottom and drift with the current as they begin transition into the dun stage. Never more vulnerable, the rising nymphs are often close enough to the surface that when the trout devour them, it creates the illusion of a surface rise.

It is a mistake to assume that every trout that creates a surface disturbance can be tempted by a floating fly. Fishing an unweighted nymph tied on a stout hook shows a preferred image at the correct depth, and can be deadly when trout are taking Green Drakes just beneath the surface.

Green Drake Nymphs & Emergers

The tendency of Green Drakes to be rather slow and clumsy in gaining full separation from the nymphal shuck makes a strong case for fishing transitional patterns known commonly as emergers. Low-floating or partially submerged patterns sharing the characteristics of both the nymph and dun stages are frequently good solutions for rising trout that stubbornly refuse high-riding dun imitations. The CDC Captive Dun and CDC Ph.D. Emerger have the disadvantage of being rather difficult to see on broken water, but they have come through for me in these situations where other patterns have failed.

Even a fully emerged Green Drake dun can experience a significant delay in gaining the ability to fly and escape the water. This becomes especially true on cooler, overcast days when lower temperature or precipitation slows the drying of wings and warming of muscles that make flight possible. A simple and sparsely dressed CDC Biot Cripple or CDC Biot Emerger with wings that slant to the rear floats in the correct position to duplicate a freshly hatched dun in this precarious condition.

A key feature of a Green Drake in the earliest phase of emergence is the vivid green and chartreuse color of the dun.

And while the intensity becomes subdued rather quickly after emergence, I incorporate the same colors in nearly all of my Green Drake patterns, with the exception of nymphs.

For more than a decade, observant anglers have attached significance to doomed mayfly duns that never gain full release from the nymphal shuck. Their logic is that a crippled insect anchored involuntarily on the surface by the shell of its former self can be recognized by opportunistic trout as an easy mark. And it does make sense that an imitation of a helpless dun in this condition would be more appealing to the fish than a healthy insect that could fly from the water at any time.

During a Green Drake hatch, I like a high-floating CDC Last Chance Cripple when fishing faster, riffled currents where the advantages of superior flotation and enhanced visibility are obvious. A CDC Biot Cripple is a lower-floating version of the same fly and is primarily intended for slower water where trout have more time to scrutinize offerings.

Green Drake Duns & Spinners

Trout behavior has evolved significantly since the time when a big Yellow Humpy worked as well as any other imitation during a Green Drake hatch.

Since being highlighted in the 1970s by Swisher and Richards, Joe Brooks, and Ernest Schwiebert, the Green Drake hatch on the Henry's Fork has attracted many of the world's most accomplished anglers. Over time, this attention has resulted in a level of trout sophistication that precludes nearly all patience for an inaccurate imitation.

Today, only a detailed duplication of the natural insect yields a fly pattern that can be fished with confidence. Fishing a dun pattern becomes a practical choice before and after the peak of daily emergence, or at times when the hatch produces a weaker volume of insects. And aided by a trout's memory of bounteous times, a Green Drake dun can produce results for several days after the hatch has ended for the year.

A CDC Biot Thorax or CDC Biot Parachute are about equal in their versatility for fast or slow water, with excellent flotation and realism. Add extra turns of hackle when the fly is to be fished on extremely turbulent currents.

A Green Drake spinner fall is typically a morning affair, and during warm weather it can come shortly after dawn. Like the other stages, the big spentwings can dominate a trout's attention even when other food sources are also available.

When in season, trout seem to be on the lookout for expiring insects that cannot leave the water, and for fly fishers the static nature of spinners makes fishing them less complicated than an emergence.

With primary consideration given to size, color, and shape, the flotation requirements dictated by the character of the current should determine how a spinner imitation is constructed. Slow, clear water permits a sparsely dressed fly consisting only of tail, body, and wings. This simple formula describes the CDC Biot Spinner, which has been my personal favorite for nearly two decades. On quicker water with a coarse current, the addition of a few turns of hackle converts the fly to a higher-floating and more visible version. The versatile CDC Hackled Spinner can be trimmed top and bottom to lower the profile if needed, and it can also serve as a credible imitation of a dun when fished as originally tied.

In the Rocky Mountain West, Green Drakes announce the arrival of another summer. On the Henry's Fork where it is most famous, the hatch is set among vast acres of wildflowers and where the tall peaks still carry a white reminder of the longest season.

The behavior of early summer trout responding to Green Drakes contrasts the experience later in the summer when the insects are smaller and the effects of angler attention begin to intensify. It is undoubtedly enthusiasm toward a more substantial reward for its feeding effort that causes a big, seasoned trout to soften its normally stern resistance to a flawed presentation of an artificial fly. And while this limited charity is purely unintentional, it becomes a gift to a beginning angler who might otherwise seldom touch a fish on pressured water.

Remarkably, these realities remain largely unchanged from my first memory of a Green Drake hatch nearly 60 years ago. And they are no less appreciated now than in the days of my youth.

As an indicator species, a population of Green Drakes speaks loudly to the health of a fishery. Trout of a size not commonly encountered are almost invariably associated with waters where the big mayflies thrive. That these waters continue to exist gives hope for the future of a sport dependent upon fragile natural resources and our willingness to protect them.

Rene Harrop is the author of Learning from the Water (Stackpole Books, 2010), and runs his own fly-tying operation, House of Harrop, from his home on the banks of the Henry's Fork.