Blue Wing Olive (BWO)

Overview: The Blue Wing Olive (BWO) commonly called Baetis, is a small mayfly species found in many freshwater streams and rivers. Known for its distinctive olive-colored wings, the BWO is a vital hatch for anglers, often occurring in cooler water conditions. This mayfly species can be found throughout the year but is particularly prevalent during early spring and fall months, making it an essential food source for trout. Nymph: The BWO nymph is relatively small, measuring around 0.5 to 0.75 inches in length. It is typically olive or light brown in color, with a slender, segmented body and a distinct dark thorax. The nymphs are commonly found in riffles and the bottom of streams, clinging to rocks and vegetation. Hook sizes for BWO nymphs usually range from 16 to 20. Dry/Dun/Spinner: The adult BWO, also known as the dun, measures around 0.5 to 0.75 inches in length. It features olive-colored wings with a distinctive blueish hue, with the body being olive to yellowish-brown. The BWO dun hatches in large numbers, often during overcast days and cooler conditions, making it a favorite for trout. The hook sizes typically range from 16 to 22. As an important hatch for trout, anglers often use parachute or thorax-style patterns for effective dry fly presentations.