Blue-winged olives (Baetis minutus)
Blue-winged olives, or commonly called BWOs by anglers, are a common sight in the spring and fall on Montana rivers.
BWOs are small mayflies with dark, olive bodies and distinctive blue-grey wings. Anglers typically fish flies in size #16-20, and a variety of patterns that imitate the various stages of its life cycle should be on hand.
On most rivers around the Bozeman area, BWOs are found in slower water nearby fast water like riffles and shallow runs. Look for back eddies, foam lines, and other places where adults will gather waiting for their wings to dry before mating in the air.
BWO nymphs make up about 80% of a trout’s diet for this species while emergers, adults, and spent adults make up the rest in nearly equal amounts.
Nymph fishing with small mayfly imitations on a tandem fly rig is a springtime standard for our Bozeman fly fishing guides on the Madison, Gallatin, and Yellowstone rivers during the pre-hatch hours.
Anglers turn their attention to fly fishing with emerger and adult fly patterns once hatching insects start to emerge in good numbers. Rising trout quickly begin to show on the surface as the hatch intensifies. BWO hatches account for some of the best dry fly fishing in Montana during spring and fall.
Cloudy, cold days bring BWOS out. The best BWO hatches happen often after a period of stable warm weather followed by a change in the weather, so be on the lookout for those to successfully fly fish this hatch.
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Category: Education
Top 5 BWO Nymphs for Bozeman Fly Fishing in the Spring
Post Date: 02/24/2024
Anglers fishing near Bozeman should be familiar with blue-winged olive(BWO) mayflies as they are an abundant food source for wild Montana Trout. These aqautic insects hatch in prolific numbers, presenting...
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