Baetis Mayfly Hatches, BWO

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Baetis Mayflies Hatches    Winter Dry Fly sight-fishing at its best.
Baetis Nymph Baetis Hackle Stacker Baetis Hair Wing Dun 
Baetis Surface Emerger Baetis Dun, Traditional  Baetis Twilight Parachute
Baetis Floating Nymph Baetis Thorax Dun CDC Angel Wing Spinner
Baetis Sparkle Dun Baetis Loop Wing Paradun Poly Wing Spinner
Compiled by: Mark Bachmann
Baetis mayflies are an extremely widespread genus.  Several species are multi-brooded and may have two or more generations per season.  The west's great fly fishing entomologist Rick Hafele, tells us that there are at least five sub-species of baetis that hatch from Oregon's streams and lakes.  Hatches can occur nearly any time of year.  This makes them common trout food and therefore very important to fly anglers. all of the streams in the Deschutes Basin have strong reoccurring Baetis hatches.  Baetis are found in both the western and  eastern United States.  The Latin name is the popular name used by the angling public. They are also commonly called  blue-winged olives.  However Baetis can also have tan or gray bellies as well.  Trout can be very selective and prefer one shade over another.  Most Baetis look gray on the water and can be quite deceptive.  It pays to catch a hatched insect and examine it closely under magnification.  Baetis are small, #16–20, but they hatch in big numbers.  The best hatches occur heaviest on over-cast, rainy days. This makes them significant early season and late season hatches. Baetis hatches go on all winter. Hatches can start in late morning and extend into early after noon. 
Baetis nymphs are swimmers.  They inhabit many water types in streams, but prefer weedy riffles and runs.  Use a "kick screen" in the morning.  If you find Baetis nymphs with wing pads that are very dark, chances are there will be a hatch during that day.  Nymphs will start getting restless in the morning.  This is a good time to pound the bottom with Baetis Nymph patterns.  Nymphs start drifting down the river and swimming to the surface in the late morning.  Some nymphs might make several attempts to reach the surface before they actually make it.  These insects are very small and don't provide much food value unless they can be taken easily in a large quantity. The best places to fish are where riffles with small graveled weedy runs enter slow pools or slow back-eddies.  The nymphs leave the bottom of the riffle and drive along the bottom for a distance.  Then they attempt to swim to the surface were the water velocity slows down. When the nymphs reach the surface of the water, their wing pads break through the meniscus.  They can hang there for several minutes as floating nymphs.  As the skin splits down the back of the head and between the wing pads the dun starts to emerge through this tear. At this point the insect can neither swim nor fly.  It is completely helpless and a perfect target for trout. The hatching duns can collect in quieter flows in very large numbers.   The trout know where these conditions regularly occur and also collect in large numbers.  Feeding is usually slow and quiet.  Look for snouts and fin tips. Some Baetis hatch before reaching the surface of the water. Watch for bulging trout that don't quite reach the surface. If you observe such activiety and your dry fly or emerger isnt't working, try trimming down a dry fly to fish it wet. Target individual fish with pin-point casting. 
The following was copied from:
Stable Isotopes Resolve the Drift Paradox for Baetis Mayflies in an Arctic River
By: Anne E. Hershey, ­John Pastor, ­Bruce J. Peterson, and ­George W. Kling­

The colonization cycle hypothesis states that stream ecosystems would become depleted of insects if flying adults did not compensate for drifting immatures. Using long—term drift and benthic abundance data, we show that a Baetis mayfly nymph population moves downstream during development in the Kuparuk River in arctic Alaska. Baetis relative benthic abundance decreased from early to late season in an upstream unfertilized river section, while simultaneously increasing in the downstream fertilized section. Baetis nymphs drifted significantly more in the upstream unfertilized section, compared to the downstream fertilized section where food was more abundant. Approximately one—third to one—half of the nymph population drifted at least 2.1 km downstream during the arctic summer. A stable isotope tracer experiment and mathematical models show that about one—third to one—half of the adult Baetis population flew 1.6—1.9 km upstream from where they emerged. These results provide a quantitative test of the colonization cycle for the dominant grazer/collector in the Kuparuk River. Quantifying the colonization cycle is essential to understanding stream ecosystem function because offspring of downstream insects are needed for nutrient cycling and carbon processing upstream. Since downstream drift and upstream flight are important components in recovery of streams from disturbances, our results provide a quantitative method for predicting recolonization rates from downstream, essential to estimating recovery.

Baetis Nymph
Baetis nymphs are swimmers.  They prefer weedy riffles and runs.  Use a "kick screen" in the morning.  If you find Baetis nymphs with wing pads that are very dark, chances are there will be a hatch during that day.  Nymphs will start getting restless in the morning.  This is a good time to pound the bottom with Baetis Nymph patterns.  Tied for the winter hatch. Mark Bachmann pattern.
Item Description Size Price To Top
06558-18 Baetis Nymph 18 3 for $5.85

Baetis Surface Emerger
Winter Baetis Mayflies can be very dark colored.  Many are jet black.  As the nymph swims to the surface The adult insect is already separating itself from the nypmphal shuck.  Bright green bands form at each abdominal segment.  As the skin splits down the back of the head and between the wing pads of the nymph, the dun starts to emerge through this tear.   At this point the insect can neither swim nor fly.  It is completely helpless and a perfect target. Mark Bachmann pattern.
Item Description Size Price To Top
06556-16 Baetis Surface  Emerger 16 3 for $5.85

06556-18 Baetis Surface Emerger 18 3 for $5.85


Baetis Floating Nymph
When Baetis nymphs reach the surface of the water, their wing pads break through the meniscus.  They can hang there for several minutes as floating nymphs.  If this happens in slower water, trout can target them at this stage and ignore emergers and duns.  A must have fly for summer hatches.
Item Description Size Price To Top
1018-18 Baetis Floating Nymph 18 3 for $5.85
1018-20 Baetis Floating Nymph 20 3 for $5.85

Baetis Sparkle Dun
Baetis duns slide from the inside of the nymphal skin out onto the surface of the water.  Their wings assume an upright position while the shuck still hangs from the rear of the abdomen.  Some are exhausted and are trapped with this shuck attached.  They become easy prey for trout. This is a proven fly for Baetis hatches, winter and summer.
Item Description Size Price To Top
1016-16 Baetis Sparkle Dun 16 3 for $5.85
1016-18 Baetis Sparkle Dun 18 3 for $5.85
1016-20 Baetis Sparkle Dun 20 3 for $5.85

Baetis Hackle Stacker Sparkle Dun
This dainty pattern was designed by Bob Quigley and is especially useful on spring creeks where trout are particularly selective.
Item Description Size Price To Top
Q1021-16 Baetis H.S. Sparkle Dun 16 3 for $5.85
Q1021-18 Baetis H.S. Sparkle Dun 18 3 for $5.85
Q1021-20 Baetis H.S. Sparkle Dun 20 3 for $5.85

Baetis Dun, Traditional
This old pattern is still very effective under a wide variety of conditions.  It can be fished as a high floater with all of the hackle intact or the bottom of the hackle can be snipped off with your leader clipper to set the fly closer to the water.  In the extreme, the hackle and wings can be trimmed down to form an emerger pattern. 
Item Description Size Price To Top
1019-14 Baetis Dun, Traditional 14 3 for $5.85
1019-16 Baetis Dun, Traditional 16 3 for $5.85
1019-18 Baetis Dun, Traditional 18 3 for $5.85

Baetis Thorax Dun
This pattern positions the wing coming out of the thorax which gives the fly a life-like silhouette and balance.  The tail is tied in as a "V" and the hackle has been trimmed on the bottom for even more realism. This is a very popular style dry fly for both anglers and trout.
Item Description Size Price To Top
1011-16 Baetis Thorax Dun 16 3 for $5.85
1011-18 Baetis Thorax Dun 18 3 for $5.85
1011-20 Baetis Thorax Dun 20 3 for $5.85

Baetis Loop Wing Paradun
This quill body, loop wing parachute is an especially good match for Baetis with lighter colored bellies.
Item Description Size Price To Top
Q200-16 Baetis Loop Wing Paradun 16 3 for $5.85
Q200-18 Baetis Loop Wing Paradun 18 3 for $5.85
Q200-20 Baetis Loop Wing Paradun 20 3 for $5.85

Baetis Hair Wing Dun
Many of the Baetis that hatch in the late fall and winter from our local streams have gray banded bellies.  This quill body hair-wing-dun is a very good match.  It is an extremely hard fly to see on the water, so we have added a fluorescent orange wing spot. If the trout are extremely selective, you may trim the wing spot.
Item Description Size Price To Top
1021-18 Baetis Hair Wing Dun 18 3 for $5.85

Baetis Twilight Parachute
This is another hi-vis dry fly. Remember that Baetis like to hatch on dark overcast days.  These are conditions which make it tough for the angler to distinguish his fly from the real ones.  Being able to see your fly can be a critical factor for success.
Item Description Size Price To Top
1022-16 Baetis Twilight Parachute 16 3 for $5.85
1022-18 Baetis Twilight Parachute 18 3 for $5.85

Baetis CDC Angel Wing Spinner
Baetis emergence and spinner falls may happen during the same period of the day.  One "hatch" can mask the other.  Duns are easy to see.  Low floating or submerged spinners are very difficult to see.  Some times when you see hatching duns and rising trout, but can't get strikes, the fish may be feeding on spinners.  This fly may be fished dry or wet.  It matches olive color spinners.
Item Description Size Price To Top
1014-18 Baetis CDC Angel Wing Spinner 18 3 for $5.85
1014-20 Baetis CDC Angel Wing Spinner 20 3 for $5.85

Baetis Poly Wing Spinner
Some Baetis spinners, especially the ones that hatch during the late fall and winter, are gray toned.  This fly can be fished dry or wet and can extend your productive fishing time.
Item Description Size Price To Top
1024-18 Baetis Poly Wing Spinner 18 3 for $5.85
1024-20 Baetis Poly Wing Spinner 20 3 for $5.85

BWO
Many different mayfly species are predominately olive colored. Others which are gray, yellow or brown have variants towards the olive tones.  Pale Morning Dun and Pale Evening Dun mayflies can be light olive or light green.  Callibaetis are usually gray or brown, but in some very rich lakes they can be light olive on the belly.  
BWO CDC Emerger Blue Wing Olive Cripple
Blue Wing Olive Sparkle Dun Blue Wing Olive Thorax
Blue Wing Olive Hackle Stacker Blue Wing Olive Loop Wing Paradun
Blue Wing Olive Paranymph  Blue Wing Olive Parachute
Blue Wing Olive Fluttering Cripple Blue Wing Olive Pearl Wing Spinner

Blue Wing Olive CDC Loop Wing Emerger

This is an excellent fly to use a trailer behind a more visible dry fly. It has nearly neutral buoyancy and barely floats, being a perfect emerger or cripple pattern. the glass bead looks like an air bubble, and bubbles naturally collect in the CDC shell-back.

Item Description Size Price To Top
1061-18 Blue Wing Olive CDC Loop Wing Emerger 18 3 for $5.85

Blue Wing Olive Sparkle Dun

A very effective dry fly/emerger, simulates an emerging dun with a trailing nymphal shuck.

Item Description Size Price To Top
1062-14 Blue Wing Olive Sparkle Dun 14 3 for $5.85
1062-16 Blue Wing Olive Sparkle Dun 16 3 for $5.85
1062-18 Blue Wing Olive Sparkle Dun 18 3 for $5.85

Blue Wing Olive Hackle Stacker Sparkle Dun

Another trailing shuck emerger/dry fly. This one sets lightly on the water.

Item Description Size Price To Top
Q1023-16 Blue Wing Olive Hackle Stacker Sparkle Dun 16 3 for $5.85
Q1023-18 Blue Wing Olive Hackle Stacker Sparkle Dun 18 3 for $5.85

Blue Wing Olive Paranymph

Parachute dry flies are always a good bet for any mayfly hatch. This one features a hackle which is tilted down in the front to force the rear of the fly below the surface, simulating a nymph hanging below the surface film. Treat the wing post and hackle with floatant. Wet the body of the fly to sink.

Item Description Size Price To Top
Q300-16 Blue Wing Olive Paranymph 16 3 for $5.85
Q300-18 Blue Wing Olive Paranymph 18 3 for $5.85
Q300-20 Blue Wing Olive Paranymph 20 3 for $5.85

Blue Wing Olive Fluttering Mayfly Cripple

Another floating nymph/emerger/cripple. Treat the hackle and wings with floatant, and the body with saliva. The front of the fly floats as the body dangles below the surface.

Item Description Size Price To Top
Q1002-16 Blue Wing Olive Fluttering Mayfly Cripple 16 3 for $5.85
Q1002-18 Blue Wing Olive Fluttering Mayfly Cripple 18 3 for $5.85

Blue Wing Olive Cripple

The best way to fish this fly is to treat the front half of the body with floatant and wet the rear half. This fly often works best as the hatch is winding down.

Item Description Size Price To Top
1069-16 Blue Wing Olive Cripple 16 3 for $5.85
1069-18 Blue Wing Olive Cripple 18 3 for $5.85

Blue Wing Olive Thorax

The Thorax Dun series are great searching flies when fishing water that has a textured surface. They can simulate several species of mayflies.

Item Description Size Price To Top
1076-14 Blue Wing Olive Thorax 14 3 for $5.85
1076-16 Blue Wing Olive Thorax 16 3 for $5.85
1076-18 Blue Wing Olive Thorax 18 3 for $5.85

Blue Wing Olive Loop Wing Paradun

Maybe on of the best mayfly dun patterns ever devised. The Loop Wing Paradun in the appropriate size will match Baetis, Callibaetis and Rhithrogena mayflies that have olive tones. To match certain hatches, you might want to color the wing posts darker gray with a felt marker.

Item Description Size Price To Top
Q210-14 Blue Wing Olive Loop Wing Paradun 14 3 for $5.85
Q210-16 Blue Wing Olive Loop Wing Paradun 16 3 for $5.85
Q210-18 Blue Wing Olive Loop Wing Paradun 18 3 for $5.85
Q210-20 Blue Wing Olive Loop Wing Paradun 20 3 for $5.85

Parachute Blue Wing Olive 
This is a have to have pattern when fishing western streams and lakes.  The wing is blue dun colored poly, which give the fly superior floatation. The wing post may be trimmed or colored with a felt marker to suit the fishing conditions.
Item Description Size Price To Top
1066-14 Blue Wing Olive Parachute 14 3 for $5.85
1066-16 Blue Wing Olive Parachute 16 3 for $5.85
1066-18 Blue Wing Olive Parachute 18 3 for $5.85

Blue Wing Olive Pearl Wing Spinner
This spinner pattern works under a wide range of conditions for both lakes and streams.  It floats well and gives a very life like silhouette.  Careful observation is the key to success during spinner falls. It is good to carry a pair of binoculars to identify what the fish are feeding on.
Item Description Size Price To Top
01100-14 Blue Wing Olive Pearl Wing Spinner 14 3 for $5.85
01100-16 Blue Wing Olive Pearl Wing Spinner 16 3 for $5.85
01100-18 Blue Wing Olive Pearl Wing Spinner 18 3 for $5.85

It’s blue-winged olive time again!
By: Rick Hafele

Dave Hughes took this fat rainbow on a little size 18 BWO nymph fishing the soft water
about 15 feet out from the bank.
Where would we be without blue-winged olives? These little guys pop up on trout streams throughout North America numerous times during the year, and the mid-winter to early spring hatch is one of the best. By late January hatches are starting to get good, by mid February they are typically great, and they usually continue to stay strong through March and into April. If you remember your bugology you'll know that BWOs belong to the family Baetidae and genus Baetis, and the nymphs, though small, are excellent swimmers. Plus, these little nymphs are either fearless or don't have brains in their tiny heads, because they routinely let go of the stream bottom and drift in the current where trout find them next to impossible to pass up. In many trout feeding studies, BWO nymphs often make up 50% or more of the food in their stomachs. And during a good hatch of BWOs, emerging nymphs are even more numerous in the drift and more frequently eaten by trout.

One of the key facts to remember about BWOs is that they are small.  A mature nymph in February may reach a size 16 if you’re lucky, and just as often you’ll need a size 18 to match them.  Another thing to remember is that during a good BWO hatch trout will at one point or another feed on nymphs swimming to the surface, nymphs hanging in the surface film while in the process of emerging into duns, and duns floating on the surface before taking flight.  What this means is that you will want to be armed with a series of patterns that match the different stages of BWOs during their emergence.  As you might imagine fly tiers have designed a wide array of patterns for this job.  The few I show here are ones I like to fish, but they by no means represent the only effective patterns out there.  Below is a brief summary of how the action might unfold during a winter day’s hatch of BWOs.

BWO nymphs are tiny swimming mayfly nymphs that frequently end up drifting in the current.  Little nymph patterns that match them are effective throughout they year.

Note the lighter color on the underside of the dun.  Dun patterns should match this color rather than the darker color on the dun’s backside.
1

This female BWO dun made it off the water but still has to molt into a spinner, mate, and then lay eggs before her life is a success.  BWO duns vary in color from shades of light brown, olive, or gray.

This is a male BWO dun, which can quickly be determined by its large reddish colored eyes.  Females always have small dark eyes.
1
10:00 am: Winter fishing doesn’t require an early start, and ten is a reasonable time to get on the water.  With no duns or rising fish in sight rig up with a nymph.  I like to use two nymphs and one of my favorite winter combinations is a size 12 green rock worm nymph followed by a size 16 or 18 BWO nymph.  Even with two nymphs you’ll normally need some extra weight on your leader to get them near the stream bottom.  Once you’re rigged fish this nymph combo wherever you find good looking trout water.  The soft water below a riffle is a great place to fish in the winter when trout are a little more sluggish from the cold temperature.
12 – 2:00 pm:  Duns will likely start showing up in good numbers sometime in this time frame. If it's a sunny day the hatch will likely be fairly light and short. If it's an overcast day with little or no wind get ready for a good hatch. If the day looks and feels like snow and a few light flurries drop from the sky, get set for a great hatch. Duns emerge from both fast choppy water and the slack water below riffles, but some of the best trout will be feeding in slow water along the edges of faster currents, and never pass by an eddy without taking a close look for a big trout feeding quietly below the foam line. During this period of the hatch you will need both emerger patterns and dries. While starting with a dun pattern is fine, if you aren't getting any action with it don’t waste too much time and switch to an emerger pattern. Fish the emerger in the film, drag-free, just like a dry fly.  This is fun fishing. Takes will be a gentle sip or slurp followed by a head shake. Just gently pull your rod tip to the side to set the hook and be ready for a strong run by a large trout. You'll probably be using 5x or 6x tippet, so you can't be too aggressive when playing a good trout, but don't baby them either, keep the pressure on and land them as quickly as possible.
2:00 – 4:00 pm:  Depending the day and conditions you might see a decent spinner fall just when the duns stop emerging.  These little spinners are next to impossible to see on the water, so pay attention to their mating swarms in the air.  If you see some mating swarms followed ten or fifteen minutes later by subtle rises with no apparent bugs on the water, switch to a spinner pattern.  In the winter spinner falls may also occur in the late morning before duns start emerging, so always stay on the lookout for them.
BWO Fly Patterns
A series of patterns that match the different stages of the BWO will be important to have in your fly box.  The patterns shown here include:  Winter Baetis Nymph (upper left); Thin Skin Nymph (second row left); Winter Baetis Soft Hackle (upper middle); Winter Baetis Surface Emerger (upper right); CDC Emerger (lower left); Hackle Stacker Emerger (second row middle); Hair Wing Dun (middle row left); Poly Wing Spinner (lower left); Pearl Wing Rusty Spinner (lower left).
Any day on a trout stream is a good one, but there's something special about a winter hatch of BWOs that get good trout up off the bottom of the stream and feeding like it's summer again.
Be prepared with an adequate fly selection to be able to capitalize on all stages of the hatch. These two links will take you to every thing you need:

The Fly Fishing Shop HOME. The Fly Fishing Shop, Welches, OR

1(800) 266-3971

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www.flyfishUSA.com

Fish long & prosper,
Mark & Patty