Michigan Flies

Hatches / mayfly

Great Speckled Olive

A

Drunella sp. (identity unconfirmed by any Michigan source)

Also called Large BWO, Drunella.

The large olive mayfly of late May on the Trails to Trout chart, hatching midday to late afternoon and peaking in the second half of May on the northern rivers. It is a much bigger bug than the Baetis olives, so when trout refuse a #18 BWO in late May try a #10-12 olive parachute or Comparadun. A robust olive nymph dead-drifted in the riffles works before the hatch. Treat the species identity as unconfirmed; only the size, color and window are documented.

#8–14middayafternoonnymphemergerdunolive to olive-brown bodyspeckled gray wingrobust olive-brown nymph

© Aiva Noringseth · CC BY · iNaturalist · Kootenay Boundary, BC · 2023

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 1 – Jul 1
    Peak
    May 1 – May 17
  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 5 – Jul 5
    Peak
    May 5 – May 21
  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
    May 15 – Jul 15
    Peak
    May 15 – May 31
  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
    May 15 – Jul 15
    Peak
    May 15 – May 31
  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 5 – Aug 5
    Peak
    Jun 5 – Jun 21

Flies that match

No patterns linked yet.