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Blue Wing Olives on Utah's Green River

The Blue Wing Olive (BWO) Hatch is the most prolific hatch on the Green River. Typically the Blue Wing Olives (a.k.a. Baetis) start popping up late March with the thickest hatches occurring from mid-April through early May. At times there are so many bugs on the water that it becomes difficult to pick out your fly among the masses. During these blanket hatches it is possible to see hundreds of trout rising. The blue wing olives on the Green River range in size from #14-20 with typical size being # 16-18. Their body color is more gray than olive, with light gray wings.

B.W.O. fly patterns for the Green River:


Parachute Adams size #16-22


Extended Body Para Baetis size #16-22


Beefus Emergers size #18-22


Higa's SOS size #14-18


Gray Soft Hackle size #16-20


RS2 gray size #14-22


Zebra Midge brown, gray, wine size #14-20


WD40 gray, wine, brown size #16-22


BWO Compardun size #16-20


BWO Spinner size #14-20


Pheasant Tail size #16-20


Spotlight Midge gray size #16-18

Blue Wing Olive Spinner Mayfly - artwork by Tim Johnson
BWO Pair
BWO Mass Shore

Green River Fly Fishing Tips - BWO's:


Fish flies 1 size larger than the naturals - When the BWO's are everywhere trout will key onto the larger bugs. Larger flies are easier for you to see and provide a more tempting morsel for the fish.


Approach with Stealth - Because of the high education level of fish in the Green River, a sloppy approach will likely alert fish to your presence. Approach at an angle that allows you to keep the fly line away from the fish - avoid casting from directly behind the fish whenever possible.


Try an Emerger behind the Dry - Trout tend to feel safer eating just below the surface film. With this method try using a parachute adams for the dry. The parachute adams has a very natural appearance and may help to avoid alerting the fish to something strange passing by. Fish the emerger tied off the bend of the dry fly hook with 18" of 6x tippet to the emerger. Use the parachute adams as your edible indicator.


Take your time - Watch the trouts feeding pattern & rhythm. Try to time your drift to pass over the fish on it's time not yours. Wait until your fly and fly line are well behind the fish before recasting.


Swing - Many bwo's will struggle with their new bodies in the new environment. Food that appears to be escaping from the trout will often trigger a strike. Gray soft hackles are deadly on the Green River and are a staple fly for most of the guides.


Try something Different - If you find that the fish are rejecting your BWO patterns try a Royal Wulff, Beetle, Ant etc. If you where eating rice all day, and a french fry came your way you just might take it instead of another piece of rice. This is typically only good for one drift over each fish.

BWO Mass
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