Blue Wing Olive

The Blue-Winged Olive dry fly imitates various small mayflies in the Baetidae family, commonly referred to as BWOs. These insects typically have olive to grayish-olive bodies and bluish-gray wings. BWOs hatch prolifically in spring and fall, especially on overcast days, and this fly mimics the dun stage as the adult rides the surface film before takeoff.

History:
The BWO pattern evolved as a refinement of traditional Blue Dun flies to more accurately represent Baetis species. Its popularity grew in the mid-20th century as fly fishers recognized the importance of these small, abundant mayflies. The BWO is now one of the most widely used dry flies in North America, with many variations tied to match regional or seasonal differences in size and color.