I love fishing with this fly. This fly pattern works great here in Utah and from what I understand is fairly common in most rivers. I have had the best of luck using olive, brown and occasionally grey colored. I really like the pattern below substituting in the colors above.
This fly comes from jayflies. This fly is simple and it works. It rides fairly low in the water which makes it a versatile fly. Due to the simplicity of this fly it can be easily modified to match many scenarios we might encounter on the river. I usually just change the hackle color and hook size. I would say using a #20. I have done #18. I have tied larger but haven not seen much use for them.
Below is the material and step by step tutorial on how to tie the blue wing olive. Enjoy
Hook: #14-22 dry fly
Thread: 8/0 UNI
Tail: Dun hackle
Body: Olive blended fur dubbing
Wing: Dun Hackle (underside trimmed flat)
1. Secure the hook in the vise.
2. Wrap the thread back to the hook bend.
3. Tie in hackle fibers (one hook length) in at the bend.
4. Dub a tapered body.
5. Tie in hackle and loosely dub the thorax.
6. Liberally wrap the hackle forward to creak a thick and buoyant wing.
7. Build a small neat head. Then whip finish and add head cement.
8. Clip the underside of the wing. This allows for the BWO to ride lower. This step can be skipped if oyou want the fly to ride higher.
Thats it. This is the pattern for a BWO that I use the most. Again thanks to jayflies for this pattern. I love it and hope others will too