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Sunriver, OR 97707
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Sunriver, OR 97707
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Fly Tying Corner

CDC Biot Caddis

Monday - December 12 2016
By Phil Fischer
CDC Biot Caddis
I still have a long way to go to fill my boxes for next season. I might be making better progress, but with all the snow hitting Mt. Bachelor, skiing has been winning out over fly tying. Go figure! But nonetheless, I have been tying with an eye on early season. An early season hatch I target each year is the Motherís Day Caddis hatch on the Crooked River. And one of the better imitations Iíve tried is the CDC Biot Caddis. The trout canít resist this pattern when the Grannom, also known as the Motherís Day Caddis, get going on the Crooked River.

The Motherís Day Caddis hatches in great proliferation on many western rivers around its namesake holiday. Sometimes the hatch can be intense and cover the water and the air with caddisflies. On our local Oregon waters, the Crooked River plays host to this hatch from approximately early-May to early June. Precise timing varies from year-to-year and is dependent on the weather.

The Motherís Day Caddis is often also referred to as an American Grannom or a Brachycentrus americanus. But it is also confused with Brachycentrus occidentalis. Not being an entomologist or expert in Latin names, I know this fly as a Motherís Day Caddis that is dark olive/gray in color, and which trout eat in enormous quantities during the hatch. That makes it a prime hatch to target on the Crooked River come Spring.

The CDC Biot Caddis pattern is designed to catch fish. The trailing shuck gives an impression of an insect having difficulty fully hatching, giving an impression that it is crippled, a trigger for hungry trout. The Biot body has segmentation to imitate the natural. The CDC underwing has excellent floatant properties, and the Whiting Coq De Leon over wing has the exact coloration of the natural. Lastly, the thorax of peacock and midge saddle hackle causes this pattern to float low in the water, which leaves it vulnerable to a waiting trout.

Cast this pattern just above rising trout and let the fly dead-drift toward the rise form. If you are not raising fish, try a size smaller or larger. Or alternatively, impart some very subtle movement on your fly with slight wiggles of a raised rod tip. Ideally, you donít want to do much more than twitch the fly. Often trout key in on fly movement and this technique can mean the difference between a take and a refusal.

Pattern Recipe:
  • Hook: Daiichi 1100, size 16-18 or Tiemco 100
  • Thread: 16/0 Veevus
  • Training Shuck: Caddis Amber Zylon
  • Abdomen: Dark Olive Goose or Turkey Biot
  • Under Wing: Natural CDC Puff in Dark Dun
  • Over Wing: Whiting Coq De Leon Hen Feather fibers
  • Thorax: Natural Peacock
  • Hackle: Whiting Dark Dun Midge Saddle (undersized by 1-2 hook sizes)
Tying instructions and steps are being published in video form, and can be found on the Sunriver Anglers Facebook page at https://www.facebook.com/SunriverAnglers/, or at the following YouTube URL: https://youtu.be/1Rp2aK8Feyo.

Experiment with this pattern during the Motherís Day Caddis Hatch on the Crooked River. If you have questions or would like additional information about the CDC Biot Caddis pattern, please donít hesitate to email me. Or if you have suggestions on future patterns to feature in this column, I welcome your input. I can be reached at Philfischer@sbcglobal.net.