The Baetis, or Blue Winged Olive (BWO), is a Mayfly found hatching in abundance on most Western waters in the spring and fall of the year. It is normally the first and last hatch of the year for anglers seeking great top water action.
There are over 150 species in North America that live in every conceivable habitat. Fishable hatches can begin as early as February and continue through April or May, then start up again in September and last until really cold weather sets in, usually around the end of October or early November.
BWOs have an incredible ability to adapt to many different conditions. They live in streams from sea level to over 10,000 feet high, from alkaline spring creeks to acidic mountain streams, and from hot desert streams to frigid arctic waters. Water temperatures are an important factor affecting distribution. The largest populations tend to occur where lush beds of aquatic plants grow in rich spring creeks, or in shallow, fast flowing gravelly riffles of freestone streams and rivers.
The life cycles of these insects contribute to their importance as trout table fare. It is common for the species to have two and sometimes three generations in a single year. The number of generations is largely determined by water temperature. Cold, high elevation or more northerly streams may produce only two generations a year, while slightly warmer streams at lower elevations or further south often produce three generations a year. Spring creeks with relatively constant water temperatures can have Baetis hatches almost every month of the year.
Variations in the size and color of BWOs occur in the same species and in the same region from stream to stream. As a matter of fact, they look more like grey winged olives. They prefer to hatch on cool, rainy, and overcast days.
Like most Mayflies, BWOs swim to the surface, break free of their nymphal shell and emerge on the rivers’ surface as an adult. At this point they drift on the surface while their wings dry. The warmer the weather, the less time they spend on the surface which makes it more difficult for the trout.
The nymph, emerger, and dun stages are the most important to fly fishers. Spinners are generally not a factor since many females of the species crawl down into the water from a rock to lay eggs.
Some of the best fishing I've ever encountered was on the Bighorn in early April during a snowstorm. On one memorable day the hatch lasted for 6 hours. It seemed as though every fish in the river (as far as I could see) was rising to size 18 duns.
While the range of patterns for BWOs is astonishing,
many of the characteristics of the better flies have similarities.
--Olive to olive-grey bodies
--Small sizes with 16 to 22 being the norm
--Predominance of CDC and dun colored saddle
--Use of synthetics for tailing
Day in and day out I believe emergers fished in the
surface film will out-catch any other creation.
1. Because these insects hatch throughout the year you should carry imitations tied in various sizes, colors, and styles. I'd suggest putting them in an entirely separate fly box.
2. Remember that insects hatching in the fall are generally much smaller than those found in the spring. Size 16′s could be huge - 18 to 24 would be far more probable.
3. When fish are actively feeding, flush-floating dries, emerger patterns and cripples will all work.
4. Once you have the right pattern getting a take requires an accurate cast with no drag. With a lot of food in the water, trout are not going to move out of the feeding lane. If you're having problems with accuracy, target fish downstream.
5. A 9-foot 4- or 5-weight outfit with a 12 foot leader is perfect. I buy 9-foot tapered leaders in 4X and add 24 to 30-inches of limp 5X to 7X tippet.
6. If you are getting refusals on flies that have been well presented and seem appear to be the right size, go to a smaller tippet before changing your fly.
7. Using a pattern that is slightly darker than the natural can help you track the fly. If you're still having trouble, tie on two flies with the small imitation as a trailer. I'll typically use a Parachute Adams in size 12 24-inches in front of the BWO.
8. When the hatch starts, it may be difficult to see the rises. If you’re floating the river, pull over and get out while taking a close look upstream along the bank. This means you're looking, not fishing! Trout feeding on Blue-Wings tend to rise subtly and rhythmically, so you should look closely for snouts and fins breaking the water surface.
9. Move slowly and get as close as you can while wade fishing. This will greatly improve on your presentation and drift.
10. When trout are picky don't waste a lot of time on a single target. Find the fish that may get overlooked. These guys will be holding right off the bank or next to some obstruction.
11. If the BWOs are particularly large, an Adams can be a good bet.
12. Try to target individual trout in the back of the pack. If you spook these fish by lining them you will probably spook the pod. Hang in there for a while; the fish may start feeding again a bit further in front of you.
13. Use a slip strike, down and slightly to the side when setting the hook. After the fish is hooked, try to steer it away from the other rising trout.
14. Try to get in a position where you are slightly off to the side of rising fish. When you cast accurately at an angle, your line and leader will naturally be to the side of the fish and not over it. If you’re approaching downstream you also want to be off to the side.
15. If nothing is working try something weird or outlandish…..nothing ventured, nothing gained!
Oftentimes the fish can really key into certain life cycles of the Baetis. Nymphs, emergers, dries, or a combination of flies will often be used. Having the proper fly can be the difference between catching fish and walking away from the river baffled. On the next few pages, FRA has put together some of our favorite patterns for consistently catching fish on the surface and in the film.
Start the thread at the center of the shank and tie in a relatively sparse tail. Tie in the quill along 2/3's of the shank back to the bend. Wrap the quill forward and tie off, or wrap both the quill and the thread simultaneously and tie off. Leave a slight amount of space between the wraps so that the thread underbody shows through. Coat the body with head cement or Sally Hansens. Click Here to order materials.
The finished product. A highly visible fly that rides low in the water. Apply some Gink and Frog's Fanny and watch this fly ride high while keeping the bend of the fly anchored under the surface of the water. Click Here to order materials.
Select a TMC108SP dolphin shank hook or bend a 1X straight eye dry/wet fly hook to the proper shape and insert it at an angle in the vise. Begin thread wraps just behind the eye. Insert the tailing material and secure down to the bend with thread wraps. Trim the tail so that its 1.5X the hook gap. After shaping the body with thread, tie in the left-over tailing material and wrap it back up to the front and tie off. Click Here to order materials.
Tie in a brown ostrich hackle and palmer it back up to the bend. An optional step is to tie in a few brown partridge feathers along the sides that extend no further than one hook eye beyond the ostrich. Select a clump of wing material and remove the underfur and long guard hairs. The length should be 1 to 1.5X the hook length. Click Here to order materials.
Flies like these will increase your chances of catching big fish on top. If a goal of yours has been to join the 20/20 club, a 20 inch fish on a size 20 fly, a Baetis hatch is a great time to do it! When the hatch is on, the fishing can be on fire. FRA wants to make sure that the odds are stacked in your favor when you see this natural wonder in action.
When there is a light snow, light rain, or nice cloud cover, get in the car and head down to the river. It is conditions like these that really get the bugs going and the fish up top. In order to have the best success, try using lighter rods: a 9' 4wt is probably the best option. Pairing a light rod with a Scientific Anglers Textured Series Trout Stalker fly line will give anglers the best advantage. This line has a much quieter pickup and lay down than other lines on the market. The taper is built to turn over longer leaders with lighter flies. The dimpling on the line allows the line to ride higher up which makes mending easier as well. Finish off your set-up with a 9' 4-6X leader some and a long piece of 5X to 7X tippet. Remember the drift must be drag free to really enjoy this hatch. Having the correct equipment makes it easier to do so.
When it all comes together this hatch is one of the year's best. If you are looking to tie up some of these great flies and are in need of materials, please click through to our Order Form. FRA also sells these custom flies that are not found in commercial fly catalogs. Feel free to browse our Online Fly Tying Department and get the materials that you need to tie up these great Fall and Spring patterns.
Thanks to FRA's new remote fly tier, Rich Strolis.
"I dig anything fly fishing. Ive been fortunate enough to have a passion that pays for itself, and met some great people along the way. I enjoy tying and creating flies about as much as I do fishing and teaching people about the sport. I'm partial to strong coffee, a good beer, big fish and no Bulls@&t. Being a father is way cool, and I have lived my life without regret." -Rich