Michigan Flies

Hatches / mayfly

Blue-Winged Olive

A

Baetis tricaudatus and other Baetidae

Also called BWO, Baetis, Little Olive.

The longest-running mayfly on the Michigan calendar, from mid-April through late October, with the biggest brood the first week of May, a second in mid-June and a third in September. Duns come off midday to mid-afternoon and are best on gray, drizzly days; the tailwaters below Croton and Tippy dams keep BWOs going through the winter. Fish a #18-20 CDC or Sparkle Dun for risers, a Pheasant Tail or olive nymph before and between hatches, and a rusty olive spinner in the evening. Sizes shrink through the season, so carry #16 in spring and #20-22 in fall.

#16–22middayafternoonnymphemergerdunspinnerolive to olive-brown bodyslate gray wingolive-brown nymphrusty olive spinner

nmacelko2 · CC0 · iNaturalist · Chester County, PA · 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
    Apr 1 – Oct 10
    Peak
    Apr 17 – Apr 23
  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
    Apr 5 – Oct 14
    Peak
    Apr 21 – Apr 27
  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
    Apr 15 – Oct 24
    Peak
    May 1 – May 7
  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
    Apr 15 – Oct 24
    Peak
    May 1 – May 7
  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
    May 6 – Nov 14
    Peak
    May 22 – May 28

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
Blue-Winged Olive Parachute (reference photo)Reference photo
Blue-Winged Olive Parachute
A
Dry fly#14–24Olive body, gray wingOlive-brown

Baetis hatch three broods in Michigan, with the biggest in early May, a second in late June and a third in September, and they run through winter on the Muskegon and Big Manistee tailwaters. Current Works lists BWOs #16 to #22 as year-round on the Upper Manistee. Fish it midday, especially on overcast, drizzly afternoons, and go down to #24 for the late-season Pseudocloeon on the Muskegon.

Dry fly

Reserve · $3.00
Adams (and Parachute Adams) (reference photo)Reference photo
Adams (and Parachute Adams)
A
Dry fly#10–20Gray (standard)Slim-bodied #10-12 for Gray Drake

Michigan's own fly, born on the Boardman, and still the default searching dry on every river in the state. Hawkins recommends a slim-tied #10 to #12 Adams for Gray Drake spinner falls at dusk on the Pere Marquette and Muskegon, and smaller sizes pass for most gray-winged mayflies from April through October.

Dry fly

Reserve · $3.00