The Blue Winged Olive hatch is one of my favorite in Colorado. Often so significant the BWO hatch can bring, what seems like, every fish to the surface. Watching these small sail boats float down the river and slowly get sipped off the surface by large trout is an amazing sight. We have turned a corner weather wise and we are starting to see Blue Winged Olives mixed in with larger Midges during the warmer parts of the day. The trout are starting to key in on Blue Winged Olives and some fish have moved into the riffles to feed on these small mayflies as they hatch.
While a Parachute Adams is usually good enough to get the job done for rising fish here are a few other patterns, both dry and wet, that are sure to put a bend in the rod when BWO’s are present.
BWO Cripple – These Blue Winged Olive fly patterns can really do some damage, especially on fish that are not committed to coming fully to the surface. The extended body sits low in the water and allows shy trout to sip it without fully committing to the surface. By adding a little floatant ant to the head of the fly you can see just enough of this BWO pattern to detect a strike. These are great in Larger Green Drake Imitations as well.
Micro Mayfly – This is a great bead head nymph pattern that can pass for a BWO or small stonefly. Try the Micro May in Olive as a lead fly and trail a smaller flash back RS2 behind it. The bead head adds just enough weight to reach fish suspended just beneath the surface. The Micro May is an excellent spring pattern for the Roaring Fork. If you can find these patterns with a black bead head thrown a couple in your fly box. While it may not make a difference I feel like the black bead makes the fly look a little more realistic. If not try using a sharpie marker to color the brass bead a darker color. This is an easy way to add variety to your fly.
Flash Back Barr’s Emerger – This one is kind of a no brainer and I am sure a lot of you have this one in the box. But, when in doubt the BWO Barr’s Emerger is an excellent fly to present during a Blue Wing Hatch. If I am nymphing I prefer this pattern without a bead head so it floats a little higher in the water column. while the bead head version of the Barr’s Emerger makes and excellent dropper pattern when fishing dry dropper.
The Bubble Back Emerger – This fly is basically an RS2 with a clear bead tied in. The bead not only adds a little weight it also looks like and air bubble surrounding and emerging insect. A great pattern to fish in shallow riffles during a BWO hatch. This fly can also make an excellent dropper pattern for fish that are feeding in foam slicks or eddies. The glass bead will sink this BWO pattern just under the surface where the foam feeders like to hang out. Try attaching a pinch on indicator a couple feet above this fly and cast it into the foam.
Foam BWO Emerger – For fish that are slow rolling in slick water this Foam Back BWO Emerger pattern is tough to beat. The foam back keeps this fly visible on the surface while the body of the fly suspends just beneath the surface. Try fishing this fly solo on a long leader to entice a strike from picky slow rolling trout. Be sure to fish it all the way through the run and let it swing before making your next cast. If it sinks a little on the swing it is not a bad thing, many times fish in the tail-out of the run will hit the fly at the end of your drift.