Dennis Collier Fly Illustration - Copyright Dennis Collier 2015Articles

A Case for Callibaetis

Click here for the DC's Crippled Callibaetis recipe and tying sequences.
By Dennis P. Collier

The regatta of tiny, speckle-winged sailboats, was riding across the liquid expanse in another "race-for-a-date" rendezvous with mayfly destiny. Occasionally, one would disappear in a subtle surface disturbance, its brief adult life interrupted by one of the piscatorial residents of Colorado's Spinney Mountain Reservoir.

A much anticipated Callibaetis mayfly hatch was underway, but the fish were showing only casual interest in the high-floating insects. As I soon learned, the answer lay in the surface film where crippled mayflies offered a bounty of easy pickings for the hog-fat rainbows and cuttbows which inhabit this wonderful fly fishing venue. The fish were selectively feeding on this easy prey which was conveniently trapped in the meniscus. But, I'm getting ahead of myself.

At last count there were over six-hundred species of mayfly residing in the waters of North America—that's a lot of bugs! And, if you hang around most fly shops for a while, you'll hear a blizzard hatch of angler talk on the subject of PMD's, BWO's, drakes, trico's, and the like. What you probably won't hear, is much conversation about those lovely little mayflies most commonly associated with stillwater destinations. Callibaetis, more often than not, take a distant back seat to the in-vogue river-borne species, perhaps because there are far more anglers who prefer to fish moving water than lakes and ponds. With that being said, I hope to change some perceptions as I offer a case for Callibaetis.

Order: Ephemeroptera; Family: Baetidae; Genus: Callibaetis; Species: ferrugineus, fluctuans, pallidus, pretiosus

Late morning sunlight dances on the water with diamonds on the soles of its shoes. A few feet above the surface another dance is underway as scores of male Callibaetis imagoes—hyaline wings glistening in the shafts of light—rise and fall in cadence, casting pheromones on the breeze in an effort to attract a mate. This ancient script will play to a predictable ending.

Female imagoes soon join the males and embrace in flight for a fleeting moment of copulation. With the brief romantic interlude concluded, male imagoes fall to the surface and expire, their role in the cycle of life complete. Female imagoes will once again retreat to nearby vegetation to incubate the now fertilized eggs and prepare for their own final curtain call. Depending on the presence of favorable atmospheric conditions, this will usually occur within a day or two. When the "call-to-action" does come, the primal maternal force will draw the female imagoes back to the well-spring of life, where they will dip and gently touch their egg-laden abdomens to the water surface, quickly depositing their precious cargo in contribution to the perpetuation of their species. Their mission now fulfilled, they too will lay spent on the surface film—wings outstretched—and die a noble death.

Unlike some species in the aquatic insect world—caddis, for example—mayflies have an incomplete metamorphosis consisting of: Egg (ovum); nymph (naiad); subimago (dun), and sexually mature imago (spinner). It is also not uncommon to experience all phases of the insect metamorphosis taking place in close proximity—with emergers, duns and spinner falls in evidence at the same time. On a number of occasions, while drifting around in my float tube, I have lifted struggling Callibaetis emergers from the meniscus and held them in the palm of my hand to observe their escape from the nymphal shuck. All the while, duns were bobbing on the waves and I was being pelted with wind-blown spinners.

Callibaetis mayfly eggs hatch within moments of arrival in the aquatic environ and the new generation of naiads will quickly head for the cover of sub-surface weed beds to embark on their own odyssey. Among the mayfly behavioral groups, Callibaetis are categorized as "swimmers" and the name is apropos considering the energetic manner in which the nymphs scurry about their neighborhoods doing what nymphs do best—eat and be eaten!

As the herbivorous naiads dine like ravenous teenagers on algae and diatoms, they grow at an astounding rate and fill the confines of their exoskeletons many times over; requiring a repeated casting-off of the old nymphal case. In technical terms this is known as instars, which is necessary to maintain comfortable living quarters for the rapidly expanding insect. Juvenile nymphs will vary in coloration depending on the aquatic environment in which they live, however, drab tan to olive/tan have been the most prevalent in my collection samples—with wing pads of similar hue, value and intensity as the rest of the body. Callibaetis nymphs come equipped with a row of oxygen-collecting gills along both sides of the abdomen, and three stubby tails—visual elements that tiers of realistic fly patterns strive to mimic.

As the nymph nears maturity it will develop distinctly darker wing pads and an iridescent halo attributed to gasses collecting between the body and exoskeleton; this in preparation for the final launch to the outside world, and emergence. During this stage the nymph will travel to and from the surface a number of times as it becomes increasingly buoyant. As one would expect, this phenomenon does not go unnoticed by the fish, as the pre-emergent nymphs openly present themselves as fair game in the unforgiving food chain.

When the magic moment does arrive for the nymph to exit its underwater world and enter the great outdoors, it will rapidly ascend to the meniscus and hang there momentarily while the subimago crawls out of the split nymphal shuck and inflates its wings with fluid. For reasons known only to the insect, it loses the center tail in the process. The newly hatched duns wear dappled-gray, cobweb-veined wings. Bodies exhibit two-toned, dark over light, color schemes. I'll refrain from laboring over body color specifics since it varies widely between Callibaetis species; gender; early to late season hatch order, and localized heredity. For the angler/fly tier looking to enhance his or her entomological knowledge—or for those who feel that an exact match is required to get the job done—sample collection of your local insect population is in order. If you're like me, your numerous fly boxes are already filled to overflowing and the list of "I should carry a few of these" never seems to end. If that sounds familiar, a Parachute Adams usually comes close enough for the purpose of catching a few fish.

This is a precarious time for these insects and many will fail to achieve eclosion, becoming stillborn casualties. Those insects that are successful in making the transformation will dry their wings and fly to nearby sanctuaries to undergo a final molt. In the process they will attain sexual maturity and become spinners. Spinners are readily distinguished from duns by their crystalline wings, which bear a dark leading edge with traces of the original mottling. During the evolution from subimago to imago, they will have also changed their cloaks to a darker color—your spinner fly patterns should reflect the hue and value differences.

In contrast to many of the bugs associated with fish and fishing, Callibaetis are multi-brooded, meaning they will offer up multiple generations of their kind during the seasonal cycle. This is a generous gesture on the part of the insect and for the angler it means if you miss one hatch, you can always try to catch the next one that same summer. Callibaetis nymphs that have resided in their underwater domains over the winter and are first in line to hatch, will produce a dun larger in size—approximating a size-twelve or fourteen standard dry fly hook—than the last arrivals of the season , which will have shrunk to a size-sixteen or eighteen standard dry fly hook.

Timing and fishing the hatch

Eclosion cycles can and do vary widely depending on the elevation and climatic considerations surrounding each water source. In Colorado and Wyoming—my home fishing turf—we can expect to see Callibaetis hatches occurring on our high-plains lakes and reservoirs from early to mid May. These events will run the gamut from sporadic and unpredictable to full-blown blizzard hatches taking place at intervals over the course of the next several weeks. In drought years, or subsequent to an exceptionally harsh winter, the customary timing of hatches can be adversely impacted; as a consequence, it is advisable to keep in touch with local fly shops that have up-to-date information.

Due to the multi-brood characteristics and extended season of this insect, it naturally interweaves with the eclosion cycles of its aquatic neighbors—namely: Giant chironomids (buzzers); damselflies; traveling sedge (caddis)—and the occasional dragonfly or water boatman. These overlaps can lead to some head-scratching guesswork on the part of the angler facing the challenge of fishing to multiple hatches; however, trial and error isn't the only path to enlightenment as to what the fish are feeding on.

Upon arrival at a favorite stillwater venue, the observant angler should do some bird watching for visual indication as to what, if anything, is happening. The first is what I call the "waltz of the swallows." Barn swallows have the uncanny ability to appear from nowhere whenever a hatch is about to take place. Birds by the hundreds will be flying low over the water surface—swooping, skimming, dipping and diving—as they hasten to get in on the dining action. This is one of Mother Nature's miracles that never cease to amaze me. Equally amazing, I don't recall ever witnessing a mid-air collision during this air-borne chaos. The second visual indicator occurs when damselflies are migrating to shore to undergo the metamorphosis into adulthood, and seagulls are lined up along the shoreline for the "all you can eat damselfly buffet." If the birds are active, you can bet the bugs are too. Next, before you even rig your rod, take a short stroll along the shoreline and see what brand of insect comes fluttering out as you brush the foliage. Now we're ready to go fishing!

An exploratory technique that I often employ, is to rig a selection of three weighted nymph, pupae, and crustation patterns on a long leader—twelve feet or so—below a strike indicator, and attached to a floating fly line. I will alternate the pattern selection depending on the season and anticipated insect hatch activity—or swap out a specific pattern if the fish start taking one fly in preference to the others . If there is wind present, I'll allow the indicator to dead-drift and let the waves impart action to the suspended stack of flies. In the absence of wind, I'll do a short strip and stop to add an enticing movement to the imitations. While this isn't my favorite method of angling, the systematic process of elimination facilitates "catching" versus just fishing.

When Callibaetis duns do start popping out on the surface film, I will immediately re-rig to a multi-fly selection consisting of an appropriately sized Callibaetis dun imitation—more often than not a size-fourteen Parachute Adams—followed by a "Crippled Callibaetis" pattern as a dropper. As suggested at the beginning of the article, I have found that fish generally demonstrate a preference for emergers and cripples over the duns during this phase, and the floating dun "strike-indicator" will usually dive under as a fish takes one of these representative cripple patterns.

For me, the most challenging aspect of fishing the Callibaetis hatch cycle in the stillwater environment is the spent-wing spinner phase. Multitudes of insects litter the surface of the water and all a fish has to do is swim around with its mouth open to inhale the lifeless bugs. Unless you can pattern a feeding fish and present your fly along an intercept path, the odds of hooking-up while blind casting are slim to none that the fish will seek out your imitation when it can randomly gorge on all the available insect flotsam. Hats off to those who can consistently catch fish during this stage, but I seldom expend a lot of time and energy pursuing lake fish with spinners. As an aside, to me, successfully fishing spinners in moving water is more easily accomplished, simply because you can allow the current to walk your fly down to the position of an actively feeding fish.

This does bring me to another thought on the subject and one that is near and dear to my heart—that of fishing streamers during a good insect hatch. Smaller forage fish will present themselves as high-protein targets as they participate in the feeding orgy, and no fish of bragging-sized proportions is likely to pass up the chance to add some meat and potatoes to the menu if the opportunity presents itself.

River Callibaetis and lessons learned

So far I have been writing in the context of Callibaetis mayflies residing in lakes and ponds, which, I might add, do offer fishable refuge during those periods when runoff-swollen rivers become unapproachable. For the uninitiated, this prolific insect does inhabit numerous slower moving river venues around the country and, where they are found, bear consideration as viable contributors to the seasonal entertainment of stream anglers.

As evidence: A few seasons ago I was doing some client guiding at a private ranch near Kremmling, Colorado and, while stream sampling sections of their Colorado River property, was surprised to find a good population of Callibaetis nymphs among the cornucopia of aquatic fish fare found in the seine. A number of mayfly species inhabit this river but I had never considered Callibaetis to be among them. A couple of months later we were fishing the ranch's lower beat on the Colorado River when a hatch of Callibaetis started coming off around noon. Soon, several tails and dorsal fins were slicing the surface on long, inside current seams. A Crippled Callibaetis pattern, tied as a dropper below a Parachute Adams, was welcomed by the foraging browns and rainbows.

Starting at the bottom of a run a fish would be hooked, pulled downstream away from the other feeding fish, fought and released, with the process repeated several more times as the hatch intensified. After the hatch had run its course, fish continued to cruise the quiet eddy areas looking for cripples and stillborns that had collected in the slack water. A Crippled Callibaetis, placed on the water surface and given an occasional twitch, caught a few more fish before they had finally eaten their fill and slipped away into deeper water. I like to use a dual-fly rig—combining both a dry and trailing emerger pattern—as a formula for success during any insect hatch. In this case, had we not found Callibaetis nymphs in our previous stream samples the appropriate patterns would not have occupied our fly boxes when the hatch occurred.

Callibaetis fly pattern rationale

My "go-to" fly during a Callibaetis hatch is now the aforementioned "Crippled Callibaetis" which Umpqua Feather Merchants added to their 2009 "new-fly" lineup. This is a fly pattern which evolved over several seasons of field testing and return trips to the tying vise; each session adding or subtracting elements in a quest to find a Callibaetis emerger pattern that would consistently catch more fish. Time was not on my side in this endeavor, since I had to tie and try my experiments based on the seasonal availability of these hatching insects, and my ability to get off work to go play. The fly, as it appears today, is the culmination of a long journey to fruition. The CDC puff and melted monofilament eyes were the last additions to a fly that was developed on the installment plan.

CDC puffs do a great job of trapping microscopic air bubbles and keeping the fly floating in the proper fashion. In fact, during our Umpqua fish tank experiments, we had to work at getting the fly to sink even though it is tied on a TMC 3761, 2X heavy-wire hook. However, experience has again demonstrated that even when the CDC becomes water logged and the fly is slightly submerged, the fish still take the cripple more often than the dun. Point being: If the fish don't care, spend your time fishing rather than primping!

I personally tie the Crippled Callibaetis on TMC #3761, 2X heavy-wire hooks for security sake. While this may sound like a contradiction for a fly that is supposed to float, the heavy wire hook prevents many a lost "monster trout" when they head for the protection of deep weed beds. This is a favorite tactic of big lake fish and nothing is more maddening than a straightened hook and lost fish when you apply the brakes to turn its head. If you mentally hesitate to use the TMC 3761, try the TMC 9300 or TMC 100 SPBL as lighter wire alternatives.

In addition to the Crippled Callibaetis, I never head for a favorite lake or river in anticipation of a Callibaetis hatch without an ample supply of my favorite impressionistic backup patterns. This includes a "flash-back" Callibaetis nymph; "flash-back" Callibaetis soft-hackle; Callibaetis "stillborn" emerger—and last but not least, a Callibaetis parachute dun imitation in sizes twelve to sixteen. Incidentally, I always tie my Callibaetis parachute dun patterns with highly visible wing materials—opaque white polypropylene yarn is my first choice—since age is taking a toll on my eyesight, and I'm almost always using them as strike-indicators as well. This is a matter of personal choice, so follow your own instincts here.

Some anglers affectionately refer to Callibaetis as "gulpers." This term has been around for decades and was originally attributed to the slurping sound big fish make while sucking in Callibaetis from the surface of Montana's Hebgen Lake. Fly patterns have even been coined with names such as "Gulper Special" in reference to the same. Others call them "speckled-wings" or "speckled duns" for obvious reason. As for me; I just call them delightful little bugs that provide a welcomed addition to my annual fly fishing pleasure. I rest my case!

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