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Dry FliesBDE Mayfly

The BDE Mayfly is a highly effective pattern that imitates the adult stage of a mayfly. Its design makes it a great choice for trout in moving or still waters, especially during a hatch.

Season
Spring, Summer
Difficulty
Intermediate
Target Species
Trout
Updated
Apr 2025
BDE Mayfly fly pattern - imitates Mayflies tied for Trout

Overview

The BDE (Big Damn Emerger) Mayfly is a parachute-style dry fly designed for maximum visibility and floatation during mayfly hatches. It typically features a dubbed body in olive or tan, a hi-vis synthetic post (like Para Post or EP Trigger Point Fiber), and a sparse hackle wrapped parachute-style. The tail is often microfibbet or Coq de Leon. It's an easy tie for a high-floating dry fly that rides low and fools picky trout.

Materials

Hook: Tiemco 100, size #12-#16
Thread: Olive 8/0 Uni-thread
Body: Olive superfine dubbing
Wing: Dun-colored CDC feathers
Hackle: Grizzly dry fly hackle
Tail: Micro fibbets in light dun

Behavior & Presentation

Natural Behavior: Females return to deposit eggs by dipping their abdomens repeatedly, then collapse spent on the surface with outstretched wings, creating distinctive silhouettes during concentrated spinner falls.

Where Trout Eat It: Fish rise methodically to intercept these exhausted adults drifting helplessly in the surface film after egg-laying.

How to Fish It: Dead drift with wings spread, matching the spent profile of collapsed spinners during predictable fall timing.

Best Water: Target tail-outs, foam lines, slicks, and current seams where spent spinners concentrate after mating swarms complete egg deposition.

Strike Type: Rhythmic, confident rises as fish feed with minimal effort during high-density spinner events offering extended surface opportunities.

Fishing Strategy

Rigging Suggestions: Fish on 5X-6X tippet with a 9-12 foot tapered leader. Can be rigged alone or as the indicator fly in a dry-dropper setup with a small emerger 18-24 inches below.

Seasonal Timing: Prime from April through August during major mayfly hatches, with peak effectiveness in May-June when Baetis, Callibaetis, and PMD hatches overlap. Most productive when water temps reach 55-68°F.

Pro Tips: Apply floatant to hackle and wing before each cast. The upright wing and visible hackle make this pattern easy to track in broken water. Size down to 18-20 during selective feeding.

Entomology

During spinner falls, adult mayflies return to the water to lay eggs, hovering in mating swarms above the surface before females dip their abdomens repeatedly to deposit eggs. After egg-laying, spent spinners collapse on the surface with outstretched wings, creating distinctive silhouettes. Fish rise methodically during spinner falls because the predictable timing and high density of exhausted adults offer extended surface-feeding opportunities with minimal effort.

Order
Ephemeroptera
Common Name
Mayfly
Organism Type
insect
Life Stage
adult

Pattern Characteristics

Intermediate Difficulty
Trout
Stillwater
Moving Water
Spring
Summer
Imitates: Mayflies
Rocky Mountain
Gunnison River
dead-drift
baetis-hatch
low-clear-water

Additional Videos