May ICU - Brown

The May ICU - Brown is a clever mayfly nymph designed by Norman Maktima, a signature tyer for Umpqua and long-time Team USA competitor. This quick-to-tie pattern features a slender body, CDC collar, and pearlescent cheeks that grab the attention of unsuspecting trout. The combination of natural materials and subtle flash makes it an effective searching pattern during mayfly activity.

May ICU - Brown fly pattern - imitates Mayfly Nymphs tied for Trout
  • Intermediate
  • Spring, Summer, Fall
  • Trout
  • Size 14

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The May ICU - Brown is a clever mayfly nymph designed by Norman Maktima, a signature tyer for Umpqua and long-time Team USA competitor. This quick-to-tie pattern features a slender body, CDC collar, and pearlescent cheeks that grab the attention of unsuspecting trout. The combination of natural materials and subtle flash makes it an effective searching pattern during mayfly activity.

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Materials

Hook
Umpqua XC400BL-BN jig hook, #14 (or Hanak H 400 BL, #14)
Bead
Slotted tungsten, 3.3mm (1/8"), copper
Thread
UTC 70 denier, wood duck
Tail
Spanish Coq de Leon fibers, pardo
Abdomen
SLF Spikey Squirrel Dubbing, rusty brown
Rib
Chartpak marker, delta brown (dark brown)
Cheeks
Veevus Pearl Tinsel, medium
Collar
CDC feathers, natural grey
Hot Spot
UTC 70 denier, fluorescent orange

Overview

Designed by Norman Maktima, who has spent over two decades as a guide and competed for years on Team USA. The pattern's slender profile and CDC collar provide movement and lifelike appearance in the water. The marker ribbing technique adds segmentation without bulk. The pearlescent cheeks give just enough flash to draw attention without being overly flashy.

Related patterns

Behavior & presentation

Natural Behavior
Clinger and crawler nymphs scuttle along cobble before breaking free into drift when disturbed or during pre-hatch activity. These nymphs tumble helplessly once swept from the bottom, vulnerable targets in mid-column.
Where Trout Eat It
Fish hold in feeding lanes 1-3 feet deep, intercepting nymphs as they drift through pocket water and channel swings.
How to Fish It
Euro-nymphing with direct contact lets you feel every tick. Lead the drift slightly to keep the fly in the feeding zone near structure.
Best Water
Target pocket water behind boulders, current breaks along riffle edges, and seams where drift concentrates nymphs into narrow feeding lanes.
Strike Type
Sharp tick or sudden stop in the sighter signals a fish pinning the nymph to the bottom.

Fishing strategy

Rigging Suggestions
Use as a point fly on a euro nymphing setup with a long, sensitive leader. Also effective under an indicator or as a dropper below a dry fly.
Seasonal Timing
through fall mayfly hatches, particularly when Baetis and other small mayflies are active. Works well from March through October in most trout waters.
Pro Tips
The copper tungsten bead provides quick sink rate to reach feeding fish in deeper water. The CDC collar adds subtle movement while the pearl tinsel cheeks catch light and attract attention.
From River & Run

Where to fish it

Rivers anglers pair with this fly, with local shops that stock it.

Open River & Run

River details and fly shops from River & Run, our sister site.

Entomology

Mayfly nymphs exhibit species-specific microhabitat preferences based on current velocity, substrate composition, and dissolved oxygen requirements, creating distinct distribution patterns across stream reaches. Their exoskeletons contain sclerotized proteins that provide structural integrity but also make them less digestible than soft-bodied larvae, yet trout still preferentially consume them due to their abundance and availability. During pre-emergence behavioral changes, nymphs become increasingly restless and drift-prone, telegraphing imminent hatches to observant fish.

Order
Ephemeroptera
Common name
Mayfly
Organism
insect
Life stage
nymph

Pattern details

  • Moving Water
  • Rocky Mountain
  • Southwest
  • tight-line-nymph
  • competition
  • dead-drift
  • baetis-hatch
  • guide-fly
  • attractor
  • searching-pattern
  • low-clear-water

Get this fly

May ICU - Brown, tied and ready to fish

Hook #14 · Intermediate