There may be as many different blue winged olive patterns as there are blue winged olive species.
For the sake of simplicity, it makes sense to cover all of these in a single entry rather than try to separate the unending variety. Everyone that fishes trout has a preferred blue-winged olive pattern and it’s not my intention to get into a debate as to which one is best.
After all, that depends a lot on geography and timing. There are thousands of blue winged olive mayflies and no single pattern is going to perfectly imitate more than a handful of them.
What Does a Blue Winged Olive Imitate
Blue winged olives refer both to a wide variety of dry flies and to several genera of mayflies – most often Baetis species, though several other genera, encompassing many more species can fall into the category as well.
Often anglers mistakenly assume that any small, blue-and-olive colored mayfly is in the Baetis genus. That’s not the case, but from a fishing standpoint it doesn’t make a whole lot of difference.
These various mayfly genera are among the most prolific breeders of any stream-dwelling insect. Their small size permits growth of up to three generations per year for many species and they often hatch in impressive numbers. As a bonus, the duns often ride at the surface for a long time before taking flight.
So, you’ve got an insect that trout are used to seeing in abundant numbers and that tends to sit within easy reach for long periods of time. It’s no surprise that they’re a favorite food source.
The Blue Winged Olive Lifecycle
Since these are hatch-matching patterns, it’s important to understand when to fish them.
The mayfly life cycle is, thankfully, rather simple. It progresses from an egg directly to a nymph stage and then to the adult stage in a process known as incomplete metamorphosis.
What does that mean for us, as anglers?
It means, mostly, that things aren’t as complicated as they could be. And, that’s kind of a refreshing change in a pastime as arcane as fly fishing.
In short, it means if there are blue winged olives in a river and you have a good blue winged olive dry pattern and a good mayfly imitating nymph pattern, you’ve got a pretty good set-up.
How and When to Fish Blue Winged Olives
These are, by and large, tied to imitate adult mayflies.
So, first things first, fish this pattern when you’re seeing a lot of blue winged olive mayflies on the water.
That said, it’s often worthwhile to try this pattern immediately after a hatch as well. Trout seem to retain memory of a good food source for days to weeks afterward, depending on how much they were able to gorge.
This is a fly that you’re going to need to present delicately.
Mayflies aren’t exactly known for being big and clumsy. They’re among the most delicate of stream-dwelling insects and your fly needs to act like it. Keep your tippet light and your delivery soft and gentle.
Some people have apparently found blue winged olive patterns that ride well through rough water, but I’ve never fished any that were especially able in those conditions.
While it depends on the conditions of your river, I’ve had better success running these patterns in slower, calmer water.
Adults versus Emergers
If you’re seeing mayflies on the surface, but you can’t seem to get trout to notice your pattern, check to see how the fish are feeding.
If fish are rolling at the surface rather than cleanly breaking it, they’re likely feeding on emerging insects rather than adults on the surface.
This is where you need an emerger pattern. This will look almost identical to your other blue winged olive patterns, but will have either no hackle, or a hackle placed very far forward on the fly.
These emerger patterns will hang the back end of your fly just below the surface – right in the zone these fish are looking at.
Variations Of The Blue Winged Olive
There are more blue winged olive variations than I could cover in a whole book.
Which ones you ought to carry depends on, more than anything, on where you are in the world. Since the thousands of mayfly species aren’t distributed evenly over the globe, you can be sure that certain species dominate in your area.
Talk to your local fly shop or other local anglers to determine what lives near you and which patterns are the best imitators. If that’s not an option, you’ll need a lot of observation time on the river.
Typically, there will be a small number of patterns that will cover all your needs. Be sure carry at least one adult and one emerger pattern no matter what, ideally in at least a couple of sizes.
While you don’t want to overburden yourself with gear, you also want to make sure you have the right tool for the job should you stumble into a hatch.