A BWO Spinner (P: troutnut.com)
As summer comes to an end and the weather starts to feel a bit more like fall, we get lots of questions in the shop about fishing dry flies during the fall months for big and hungry trout. While most of the insects have hatched out during the summer months, and colder temps make fishing terrestrials a bit more difficult, fishing dries can become tough. Lucky for all of us that don't want to switch to indicator tactics any earlier than we have to, cloudy fall days can produce great hatches of Blue Winged Olives, also known as BWO's or baetis. When BWO's show up fish take notice, and you don't want to be unprepared when they do. I wouldn't call them any sort of secret, but the fall BWO's are an often overlooked hatch.
BWO's are usually smaller in size (16-22) and hatch in large numbers, usually blanketing the water as duns which is what makes the fish go crazy. With clear wings, olive to olive-brownish bodies BWO's are most prominent during spring and fall months, before the weather gets to warm or to cold. Slow moving water and back eddies are the best places to look for fish eating baetis, as the duns stay on the surface drying their wings for quite some time. Emerger patterns are most productive during the hatch. When fishing a large hatch, you might try a dun or cripple pattern that is slightly darker than the natural. The trout usually don't get extremely picky, and it's easier to see your fly among the hundreds of bugs on the water.
Good fly imitations are Parachute Baetis, Sparkle Duns, Thorax Duns, Rusty Spinners and Comparaduns.