Blue Wing Olive

Materials

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Hook TMC 100 #16-20 or TMC 102Y #15-19
Thread Danville Flymaster 6/0 Light Olive
Body Blue Wing Olive Superfine
Tail 8-12 Medium Dun Spade Hackle Fibers
Wing Dun Hen Hackle Tip
Hackle Medium Dun Hackle
Actual Blue Wing Olive
Actual Blue Wing Olive

Blue Wing Olive

Life Cycle

The Blue Wing Olive mayfly might be considered to begin its life cycle on the bottom of the stream or river as a nymph. The nymph will spend 2-3 months within this form undergoing multiple moltings. When conditions are favorable, ie a cold rainy day, the nymphs will rise to the surface to “hatch”. BWO nymph’s are, generally, good swimmers hence with a torpedo-like in shape.  Often, the nymphs will quickly swim to the surface when they are ready to “hatch” or they take their time and drift for a period of time. Once the nymph reaches the surface, the nymph has to penetrate the surface film with the top of its back and split open.

A dun emerges from the nymphal shuck and lofts into the air. Additionally, the dun may also ride on the surface with extended legs as the wings dry before lifting off for streamside vegetation.  BWO’s are rather small, in sizes 16 to 20, and are vulnerable during this time of emergence. Once the duns are able to get upon the vegetation, they will molt into spinners and the males and females will finally mate. Eventually, the female will return to the water surface to lay eggs. Some females will actually swim back down to the river bottom and lay the eggs directly onto the streambed.  Finally, the females will expire on the surface with it’s wings outstretched, this is known as the “spinner fall”.

Hatches

Primarily, Blue Wing Olives prefer to hatch when it’s cool and drizzly, often in early to mid-afternoon. While fishing on our Sierran streams you will most likely encounter hatches during late September through November. Overall, hatches will not show up during the hot months of summer or when the winters are brutally cold. However, another hatch period is in the Spring during March through June. Indeed, hatches might occur at any time. Typically, the life cycles are short, only 4 months. Ultimately, there might be 2-3 generations of BWO’s each year. The spinner adults will have varying shades of olive, gray, and brown. The wings will chiefly have a dark and smoky/blue color.

The streams or rivers with the greatest concentrations of Blue Wing Olives will have slow to moderate flowing water. Generally, back eddies can be very productive as well as foam lines.

Patterns to consider

Within the dry fly category, we have Blue Wing Olives with the standard Catskill pattern, Extended Body, and the Thorax Dun. The emergent forms are very important as the fish key upon this stage. Parachute patterns often cover this emergent form by presenting the body of the fly within the surface film.  In particular, Parachute patterns allow for good visibility with a Hi-vis wing post. However, other important emergent forms are the RS2, Brooksprout, and CDC Dun. Another good fishing tip is to use a BWO dry fly with a BWO emerger trailing the dry by 24 inches.

Lifecycle of BWO

Lifecycle of BWO

Other Patterns

Thorax Dun BWO
Thorax Dun BWO

Thorax Dun, BWO

Hook TMC 100 #16-20
Thread Uni-thread Olive 8/0
Body Golden Olive, Superfine
Tail Light Dun Microfibetts
Wingpost Medium Dun Turkey Flat
Hackle Light Dun Hackle
Paraquill, BWO
Paraquill, BWO

Quilled Parachute, BWO

Hook TMC 100 #16-20
Thread Uni-thread Olive 8/0
Body BWO Dyed Quill
Thorax Blue Wing Olive Superfine
Tail 8-12 Medium Dun Spade Hackle Fibers
Wingpost White Turkey Flat
Hackle Medium Dun Saddle
Parabiot BWO
Parabiot BWO

Biot Body Parachute Dun, BWO

Hook TMC 100 #16-20
Thread Veevus 14/0 Gray
Body Olive Turkey Biot
Thorax Olive Superfine
Tail 8-12 Medium Dun Spade Hackle Fibers
Wingpost Z-lon Dun
Hackle Medium Dun Saddle
External May, BWO
External May, BWO

Extended Body, BWO

Hook TMC 2487 #16-18
Thread Uni-thread Olive 8/0
Body Olive Hollow Tubing, standard
Thorax Blue Wing Olive Superfine Dubbing
Tail 3 Olive Microfibetts
Wing Medium Dun Hen Cape Hackle
Hackle Grizzly Dun Hackle
Brooksprout, Baetis
Brooksprout, Baetis

Brooksprout, BWO

Hook Daiichi 1120 #16-22
Thread Uni-thread Olive 8/0
Body Olive Turkey Biot
Thorax Blue Wing Olive Superfine
Shuck Olive Brown Z-lon
Wingpost 1/16
Hackle Light Blue Dun Hackle
CDC Dun Baetis
CDC Dun Baetis

CDC Dun, BWO

Hook TMC 103bl #19-21
Thread Uni-thread Olive 8/0
Body Blue Wing Olive Superfine
Thorax Blue Wing Olive Superfine
Tail Light Dun Tailing Fibers
Wing Med Dun CDC
Hackle Ginger Hackle