Michigan Flies

Hatches / mayfly

Light Cahill

A

Stenacron interpunctatum and Maccaffertium spp. (species not confirmed by Michigan sources)

Also called Cahill, Stenonema, Stenacron.

The pale summer clinger of June through mid-August, coming off in the afternoon and evening on the Upper Manistee, Au Sable and Muskegon. Hatches are scattered rather than heavy, so the Light Cahill is often a searching pattern: a #12-14 cream parachute fished through riffles and pocket water on summer evenings. Spinners fall at dusk over the riffles. A Robert's Yellow Drake covers Cahills, Sulphurs and Brown Drakes in one Michigan pattern.

#10–14afternooneveningdusknymphdunspinnercream to pale yellow bodypale yellow to cream wingtan clinging nymph

© Patrick Hanly · CC BY · iNaturalist · Ionia County, MI · 2021

Timing by region

  1. Southeast Lower Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    May 22 – Jul 31
    Peak
    —
  2. Southwest Lower Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    May 26 – Aug 4
    Peak
    —
  3. Northeast Lower Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    Jun 5 – Aug 14
    Peak
    —
  4. Northwest Lower Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    Jun 5 – Aug 14
    Peak
    —
  5. Upper Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    Jun 26 – Sep 4
    Peak
    —

Flies that match

Pheasant Tail Nymph (reference photo)Reference photo
Pheasant Tail Nymph
A
Nymph#10–20NaturalBeadheadFlashback

Old Au Sable Fly Shop names a #12 to #14 Pheasant Tail as the Hendrickson nymph, and it covers every Michigan Ephemerella and Baetis nymph before and during a hatch. A beadhead #10 is a standard trailer fly in U.P. steelhead rigs, and #12 to #20 versions take pink salmon in clear water. Fish it dead-drifted under an indicator or on a tight line in the weeks before each mayfly hatch.

Indicator nymphing · Euro / tight-line nymphing

Reserve · $2.75
Rusty Spinner (reference photo)Reference photo
Rusty Spinner
A
Dry fly#12–20Rusty brownRust with clear wings

Supinski's Muskegon chart says 'rusty spinners at dark' for Sulphurs, and the same fly covers Hendrickson, Cahill and March Brown falls over riffles at sunset. Fish it flush in the film at dusk from May through July when you see spent wings in the foam lines.

Dry fly

Reserve · $3.00
Roberts Yellow Drake
A
Dry fly#4–18Yellow (deer-hair body)Yellow tied large for Hex

Grayling's all-purpose pale mayfly, an extended deer-hair body under a parachute post, sized #4 through #18 to cover Sulphurs, Cahills, Brown Drakes and the Hex. Hawkins names a large Roberts Yellow Drake as a Hex dun and spinner; fish it after dark in late June on a short 6 ft 2X leader. Every Au Sable shop stocks it.

Dry fly

Reserve · $3.00
Gold-Ribbed Hare's Ear (reference photo)Reference photo
Gold-Ribbed Hare's Ear
A
Nymph#8–18NaturalOliveBeadhead

The generalist buggy nymph for Michigan's clinger mayflies and caddis pupae, and MidCurrent lists a #10 to #14 Hare's Ear among winter steelhead nymphs. Dead-drift it under an indicator all season for trout, and as a trailer behind an egg or stonefly for steelhead.

Indicator nymphing · Euro / tight-line nymphing

Reserve · $2.75
Light Cahill (reference photo)Reference photo
Light Cahill
A
Dry fly#10–14CreamPale yellow

Cream Stenacron and Maccaffertium mayflies hatch from early June to mid August, 2 pm to 10 pm, and carry the evening fishing after the Hex on the Upper Manistee, Au Sable and Muskegon. Fish a #12 to #14 cream parachute or Catskill tie in the last two hours of light through July and August.

Dry fly

Reserve · $3.00