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Cahill Comparadun
A emerger, tied #14–18, a summer pattern. It is tied against 3 named insects in this book — May–September.
- #14–18Hook size
- emergerType
- SummerSeason
- 3Hatches matched
What it looks like
A drawing, not a photograph, and not traced from one. Its proportions were read off 5 independent reference photographs of the pattern and written down as 5 measured characteristics — wing angle, tail length against the shank, how far a hackle fibre reaches — every one of which had to hold across more than one of them before it could be drawn. What survives across many photographs of a fly is the fly.
What it imitates
Each of these is the same hatch record the app's own panel reads, so a pattern recommended on a river card in the app is recommended for one of the insects below.
- Cream Cahill Maccaffertium modestum · July–August · 62–74°F · #14–16
- Light Cahill Maccaffertium ithaca · May–July · 55–68°F · #12–16
- Little Yellow May Leucrocuta / Heptagenia spp. · June–September · 58–70°F · #16–18
Tying recipe
In tying order. This dressing is the standard one — these patterns have been in the publicrecord for decades — and materials substitute freely: the proportions and the silhouette are the pattern, not the brand of dubbing.
| Hook | Standard dry-fly hook, sizes 14–18 |
|---|---|
| Thread | Cream 8/0 |
| Tail | Split microfibetts |
| Body | Cream-yellow dubbing |
| Wing | Deer hair, fanned 180 degrees |
| Shuck | Amber Z-lon, optional |
When to fish it
The change-up when a standing dun starts getting refused. It sits in the film rather than on it, which is where the naturals are.
A summer pattern. The insects it matches are active may–september, in water from 55°F to 74°F.
Target species
- Trout
Rivers it fishes well
Rivers with a page here that sit in the regions where the insects this pattern imitates are recorded. It is a claim about coverage, not a report of a fish caught.
- Au Sable River northern lower Michigan · July mean 72.1°F
- Catawba River the North Carolina mountains · July mean 76.7°F
- Jackson River the Virginia mountains · July mean 66.3°F
- Muskegon River northern lower Michigan · July mean 71.0°F
- Escanaba River the Upper Peninsula · July mean 68.3°F
- Saint Croix River northern Wisconsin · July mean 77.2°F
- Smith River the Virginia mountains · July mean 51.9°F
- Tygart Valley River the Virginia mountains · July mean 74.6°F
- Kalamazoo River southern lower Michigan · July mean 71.3°F
- Aaron Creek the North Carolina mountains · July mean 76.7°F
- Aaron Run the Virginia mountains · July mean 77.1°F
- Aarons Run the Virginia mountains · July mean 74.2°F
Related patterns
Same type of fly, or tied for the same insects.
- BWO Comparadun emerger · #18–22 — Flush-floating. Baetis emerge in the film and the fish know it.
- LaFontaine Sparkle Pupa emerger · #12–18 — The gas-bubble pupa. Fished rising through the swing, which is how caddis actually emerge.
- Little Black Caddis Pupa emerger · #16–20 — Dark body, sparse soft hackle. Swung through the tail of a run in April, which is where the naturals are going.
- RS2 emerger · #16–24 — The emerger that saves a hatch you cannot otherwise crack. Fish it in the film.
- Rusty Spinner dry fly · #14–20 — Almost every mayfly spinner is rust-coloured. This covers the last hour of light.