How to Fish a Blue Winged Olive (BWO) Pattern

One fly pattern that symbolizes the beauty and challenge of fly fishing, is the Blue Winged Olive (BWO). Revered by fly anglers across the globe, this pattern imitates the mayfly species. BWOs are found in many waters and are a critical food source for trout. Imitating miniature sailboats on the water they can come in waves that look like a satellite video of the America’s Cup from thousands of feet from the air. In this article, I’ll delve deep into the tips and techniques that can make your BWO fishing experience both fruitful and enjoyable.

Try reading the "Identifying the Blue Winged Olive (BWO) Fly and Hatch" as it will prepare you for how to fish a BWO.

Understand the Life Cycle of BWOs

BWOs, like all mayflies, have four life stages: nymph, emerger, dun, and spinner. Being aware of these stages and the time of year they’re most prevalent can help determine which fly pattern to use. If you want to learn in detail about this, read the article I wrote called, “Mayfly Identification.”

Select the Right Fly

You may have heard me say before that a best practice is to select patterns in the order and format of observation, silhouette, size, and color then present them well. BWOs generally range from size 18-24. However, during certain times of the year, larger (size 16) or smaller (size 26) BWOs might be present. Pay close attention to the naturals on the water and adjust your fly size accordingly.

How to Fish a BWO by Matching the Hatch

This is a fundamentally sound technique when in fly fishing and is used by many.  My particular position on the technique is that it is significantly more effective when dry fly fishing verses nymphing.  Fish are primarily opportunistic feeders and will almost always aim to go after what is available.  In many top water hatch scenarios, the food type is so prevalent I believe it allows them to key in on certain characteristics and make effective decisions more rapidly. Doing so, they know they can feed well, avoid mistakes, and are less worried about predators, etc. If trout are feeding on emergers, for example, then using a dry fly pattern might not be as effective. Instead, choose a BWO emerger pattern to fish just below the surface.

Master the Drift:

A drag-free drift is crucial when fishing. How to fish a BWO pattern is no different. Whether you're fishing with a dry fly, emerger, or nymph, ensuring that your fly drifts naturally with the current can make all the difference. As mentioned earlier, the presentation aspect when selecting a fly is by far the most important.  What I mean is that you have to consider the water type you are fishing, where the fish is feeding, and what fly is best for the presentation. Is the fly buoyant enough? Are the currents drowning flies and fish are eating then? Are the fish eating on top or emergers? Are the fish eating spinners? Do the BWOs they are eating in different phases? Are the BWOs floating high or low?  Observation can be key in determining the characteristics of the fly being chosen. Use the SSF Formula for systematizing your cast for a perfect drift. 

The Sacrificial Zone, Sight Zone, Feeding Zone Formula (SSF)

• Sacrificial Zone = Landing the fly far enough in front of the fish that it is not yet within their line of vision.  You do not present far enough ahead that you line spoke them and is a short section of the presentation can be sacrificially poor. The primary desire is it is to set up your fly to enter the Sight Zone and exit the Feeding Zone in a perfect drift.
• Sight Zone = The area in which a fly first comes into the fish's sight. The presentation of the fly has to be shown properly by this stage of the drift.  This way, the target fish can take action on it without hesitation.
• Feeding Zone = The space in which you believe the fish will eat. An area that is determined through observation and can be defined as how far a fish will move to feed on the fly. I think of this as a sphere of opportunity. In all directions, how far are you observing that the fish will move to eat? Ahead, below, left, right, up, or down are all in consideration. 

Focus on Riffles and Runs

BWOs typically hatch in faster-moving water, so focus your efforts on riffles and runs. Trout will often position themselves at the tail end of these faster sections, waiting for the emerging BWOs. In many cases, I will fish further back, making the attempt to catch a fish and pull it back away from the riffle to keep the pod of fish unaware of a disturbance. Then I reset and move forward.  On other occasions, I will target the head of the pool. This can be determined by the quality of the target fish.  If I see a target that outweighs the others in quality, I’ll often go there first.

Adjust to Weather Conditions

BWO hatches can often be highly influenced by the weather. Overcast and drizzly days are prime times for BWO hatches. These conditions can also be beneficial to an angler as they can cause natural water disturbance that will hide your presence in location and presentation.  Investing in a high-quality pair of polarized glasses that are low light sensitive, like a yellow lens, can be the ticket to a great visual day of fishing.

Don't Forget the Spinner Fall

After mating, BWOs return to the water as spent spinners. These can form large mats on the water surface, and trout can feast on them. Observe the water’s contents below the riffles, in eddies, etc.  When you see masses of spinners floating in the river, it can be advantageous to change your setup to a spinner-only dry fly or, one of my favorites, a slightly larger adult dun with a trailing spinner about eighteen inches off the back.  The forward fly will help you see where approximately the back fly is, and you may even get an eat there, too. Using a BWO spinner fall pattern or generalized spinner patterns during these times can be very effective.

How to Fish a BWO and Experiment with Techniques

While the traditional dead drift is a go-to method, sometimes, imparting slight action like a twitch or slide movement to your BWO pattern can induce strikes. This imitates the struggling motion of the natural insect. I tend to do this with crippled fly versions as I presume they can often be more active in the struggle to lose their tailing schuck.

Observe and Adjust

Let’s recap our discussion on observation. Always pay close attention to the behavior of the fish, their environment, and the natural insects. The clues to success are in these observations.  Remember that the majority of your fishing is matching your observation, and your wins will likely come from there. In reality, very few opportunities are created when fishing. Again, the majority are found in observation. For example, If you notice trout sipping just below the surface, but they're ignoring your dry fly, it might be time to switch to an emerger or soft hackle pattern. If fish are being picky in slack water, then look for moving water.  Sit and observe, pump a stomach, etc., but be a detective or scientist who is looking for clues to solve the puzzle. 

Technical Example: When fishing an emergent pattern, try giving your line a slight twitch every few seconds. This can make your fly look like an emerging BWO trying to break through the water's surface.

The allure of fly fishing often lies in observation and its intricacies when learning how to fish a BWO pattern. BWOs exemplify this pattern, and while it might seem daunting at first, with observation, patience, and practice, you'll find success on the water. So the next time you're out on the stream, and the BWOs start to hatch, remember these tips, and you'll be well on your way to a rewarding fly fishing experience.

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