May 8, 2016
May, 8, 2016
BLUE WINGED OLIVES
Below you will find a version of my handout regarding the Blue Winged Olive mayfly (aka Baetis) which Members can find on the rack inside the door of the Sign-In Wagon. I’m posting the handout as a blog entry now, before the season even begins, because I am starting to see Blue Winged Olives on the Ranch water on a consistent basis and because anglers will encounter BWOs on other waters this time of year.
Day in and day out throughout the season, there is a possibility that anglers will run into BWOs, whether they are fishing Silver Creek or some other river. Trout will often respond to BWO patterns even when a hatch is not visible to the angler, or is not present on the water to begin with, because fish are used to encountering BWOs most weeks during the season. The question is which species of the Baetis family is the culprit. On Silver Creek we are blessed with spring hatches, summer hatches and fall emergences of a variety of BWO species. Some BWO species are larger than others, some are gray, some are dark olive, some are pale olive and we even have a tan bodied Baetis during the heat of August which is a size 26!
In my view the most important characteristic for BWOs is size, followed by the pattern’s profile, then color. This may be why anglers have consistent success fishing the BWO hatch with the classic Adams dry fly, the Parachute Adams, the Female Adams (with a yellow butt that imitates an egg sack) and other variants.
Your Stream Keeper’s approach is to maintain a selection of a few dry patterns in a range of sizes and a variety of body colors. I tend to favor the Hatch Matcher, the No Hackle, the Hackle Stacker; the Pulled Down CDC Winged Parachute and the Sparkle Dun. I like to carry these patterns in size 16 to size 22, if I can tie them or buy them that small. I always carry these patterns in a spectrum of body colors, including gray, pale olive, standard olive and dark olive. I don’t feel that the shade of dun hackle is that important, except that I prefer dark dun hackle for Fall Baetis.
B. Tricaudatus, B. Vagans, B. Parvas, Pseudocloeon, . . . . names that we embraced or have been pushed on anglers in the past . . . . . are part of the Baetis Complex that consists of at least 60 species in the Baetidae family. For decades entomologists debated species identification and renamed species based on structural criteria; as of late, the debate rages on fueled by DNA analysis. However, for fly fishermen field identification is irrelevant as the behavior of the Baetidae complex is generally consistent throughout the 60 species.
All we need to focus on is the size and color of the insect present on Silver Creek, the stage of the hatch that immediately confronts us, and what will likely happen next. Trout will feed on members of the Baetidae complex whenever they get a chance at them, without bothering to identify them to species level.
Fly patterns devised under the old classification systems still work under the new nomenclature as they did in the past, although we may have to adjust color and size as we encounter species new to us on water new to us. Despite sporting new names, the insects themselves display the same old shapes, colors, sizes, and hatch on their old waters according to the same annual and daily schedules. Many prefer the generic label Blue Winged Olive, and most writers regard the BWO as the most important bug for trout over the season. Most of us have observed that trout frequently key on BWOs even when a larger insect hatching at the same time.
Emergence & Duration. Predicting the time of emergence is not difficult if one keeps several principles in mind. First, BWOs tolerate heat and sun only to a limited degree. For that reason, in the early season there generally is one emergence during “banker’s hours,” whereas as the sun dominates one may encounter an early morning hatch and an emergence towards the end of the day. For the same reason, cooler overcast weather will result in a more protracted but sparser hatch. A more truncated and denser hatch may attend a hot sunny day; indeed, the BWO hatch may be over before you realize it has started.
HATCH PROGESSION.
Nymphs.
Nymph activity during the “pre-hatch” period is often more important for the BWO complex than other mayflies. BWOs are considered “swimmer” mayflies because they freely propel themselves in 3 to 5 inch bursts across the stream via quick pulsing movements of the abdomen combined with flips of the tail. For that reason, fishing a blunt nymph pattern or a dark soft hackled fly across the creek using the traditional “wet fly swing” presentation can be very effective before the hatch. Your Stream Keeper’s favorite patterns for this pursuit include: #14 to #18 Pheasant Tail Soft Hackles tied with red-dyed pheasant tail fibers; a plain old Pheasant Tail Nymph; Mercer’s Poxyback BWO Nymph (available from The Fly Shop in Redding, CA); and the BWO Nymph featuring dark olive or olive tan dubbing to match the natural.
One needs to be very observant as often the visible “rises” are really nothing more than the backs of fish that are feeding on nymphs just below the surface; pounding the water with Dun patterns or emergers may yield the occasional fish but it is not necessarily the more efficient or productive presentation.
Emergers.
Emerger patterns can be very important when fishing a BWO hatch. The surface film can be a rather formidable barrier for this small insect especially on smooth currents and calm days; a greater percentage of “cripples” will be present under these conditions. However, the BWO has an easier time escaping the surface film on “broken” water created by wind. Conversely, when BWOs hatch on calm glassy flats many more of them will fail to make it through the meniscus. One needs to be vigilant and fish “emerger” patterns when a significant number of “cripples” is observed.
Your Stream Keeper’s favorite emerger patterns include: the BWO Sparkle Dun; Quigley’s BWO Cripple; Rene Harrop’s BWO Cripple.
Duns.
To many anglers the emerged BWO Dun provides the greatest sport of the hatch; suddenly, the surface is blanketed by little dark green ships with gray sails. Some days it seems like every fish is vulnerable to a dun conspicuous dun pattern cast three feet above a working trout; on other days one can’t buy a fish.
Your Stream Keeper’s favorite BWO Dun patterns include: the Reverse Tied CDC Winged Parachute; the BWO Hatch Matcher; the Olive Sparkle Dun; Quigley’s BWO “Hackle Stacker;” the olive Hair Winged Dun; and the BWO CDC Biot Comparadun.
Spinners.
After emerging and leaving the water, the BWO transitions into a “spinner,” mate in flight, and later return to hover over the stream, with the female intent upon depositing their fertilized eggs on the surface. Some BWO females will actually dive into the water and some creative tyers have designed patterns to imitate this behavior. When fishing spinner patterns to “sippers” along the bank in the evening, most any cripple pattern will work provided that the body is either a shade of olive or rusty brown in hue, such as the Blue Quill Spinner or the Red Quill Spinner, respectively. The standard Rusty Spinner is a productive pattern for the Baetis spinner fall.
Doug Andres
Stream Keeper, Double R Ranch