Tying the Blue-winged Olive

News & Tips: Tying the Blue-winged Olive

A fly tying how-to guide with step by step instructions.

Found on streams throughout the United States, the Blue-winged Olive (BWO) mayfly is a staple food source on which trout rely year round. If the weather is cold, clammy and wet, chances are good that trout will be actively feeding on Blue-winged Olive duns. During these types of overcast conditions trout will feed during the warmest part of the day, giving anglers a good chance at presenting dries to rising fish.

Blue-winged Olives mainly hatch throughout cooler temperature ranges and well into the winter, making these fly patterns a must for any serious fly angler. Adult flies look like little tiny sailboats drifting softly on the water's surface. These duns often have olive bodies and wings that vary from light gray to black.

These mayflies are known to hatch in slow to medium riffle runs that lead into slower water. Fly anglers should be conscious of this hatching behavior and key on spots where the current funnels floating insects from a fast run to a deep pool where fish can lay in stealth.

Since BWO size varies throughout the year, it is a good idea for fly anglers to carry dries that range from size 16 all the way down to a tiny size 24. At first glance, dries this small seem to be almost inconsequential to a large trout's diet, but don't be mistaken. A size 24 may be hard for anglers to see on the water's surface, but selective trout easily find them. Fly anglers fishing the wrong size BWO during a hatch often watch in frustration as feeding fish ignore their fly drift after drift.

Use traditional dry fly tackle to fish BWOs. Nine-foot fly rods (stream environment permitting) and floating lines should be all you need. Standard nine- to twelve-foot leaders tapered to either 4X or 5X are ideal for presenting dries softly to fish. Fishing tiny dry flies does not have to be a daunting task. A trick for fly anglers is to use a dropper leader system which puts a larger dry (size 16 or 18) about a two to three feet above the smaller dry. This system allows the angler to spot the larger fly and follow it down to the tiny size 24 fly more easily. BWO's might not be the biggest hatch you will come across, but fishing these dry flies before the sun warms things up will likely get fish rising.

Materials List for Tying the Blue-winged Olive

Hook Dry Fly Hook, size 18
Thread Olive Uni-Thread, size 8/0
Hackle Blue Dun Dry-fly Hackle, size 18
Tail Blue Dun Dry-fly Hackle Fibers
Body Olive Super Fine Dubbing
Wings Blue Dun Dry-fly Hackle Tips


Step-by-Step Instructions Tying the Blue-winged Olive

Step 1 — Place your hook in the vice and secure tightly in place. bwo1
Step 2 — Attach the thread to the hook shank at the 3/4 mark on the shank. bwo2
Step 3 — Select and align the tips of 12-15 blue dun dry-fly hackle fibers. Tie these fibers onto the hook shank at the point above the barb. They should be about 1 1/2 times the length of the hook gap. bwo3
Step 4 — Select and align two blue dun dry-fly hackle tips so that they flare away from one another when held back to back. The wings, when finished, should be approximately the length of the hook shank. bwo4
Step 5 — Strip all the hackle barbs off of the feathers leaving just the tips. Tie these tips down to the hook extending over the hook eye at the 3/4 mark on the shank. bwo5
Step 6 — Stand the wings upright and place several thread wraps in front of the base to keep them in place. bwo6
Step 7 — Advance the thread back to the rear end of the shank and pinch dub your thread very lightly with the super fine dubbing. Build a small tapered body up the hook shank, stopping just behind the wings. bwo7
Step 8 — Strip the bottom section from a blue dun dry-fly hackle, leaving the stalk exposed, and tie this just behind the wings. bwo8
Step 9 — Advance the blue dun dry-fly hackle up the body of the fly, taking four to five turns of hackle behind the wings and three turns in front of the wings. bwo9
Step 10 — Build a small neat head for the fly, whip finish the thread and cement. bwo10