Green Drake

Telling it apart

• Very large: size 8 to 10, a 20–25 mm body.
• The dun has a creamy-green body blotched with dark brown.
• Wings heavily barred with brown, and very tall.
• Three tails.
• The spinner (Coffin Fly) is an almost plain creamy white with clear, glassy wings — it looks like a different insect entirely.

Why ten days and not six weeks

The brevity is not an accident — it is a strategy. By emerging all at once in a very narrow window, Ephemera guttulata simply saturates its predators. Trout, birds and bats eat all they can, and enough still survives to breed. A hatch spread over six weeks would be eaten almost entirely.

The corollary for an angler is brutal: turn up a week early or a week late and you have missed the whole year. And because the trigger is thermal, the date moves ten days either way between seasons.

Two insects, two names, two kinds of fishing

The dun is the Green Drake: creamy green, blotched, barred wings. Twenty-four to forty-eight hours later it moults one last time into the spinner — and becomes unrecognisable. White, smooth, with clear glassy wings. English anglers named it the Coffin Fly for that pallor.

The two stages fish differently, and often the spinner fishes better. The Coffin Fly fall happens at dark, later than the hatch, and is far more concentrated: thousands of dead insects lying flat and motionless on the surface. That is when the best fish in the pool commit.

Green Drake selectivity

This is one of the few hatches where a trout will refuse an enormous, perfectly drifted fly again and again. The usual reason: it is not eating duns at all, it is eating emergers — insects stuck half out of the nymphal shuck and unable to escape.

If you take three clean refusals on a good drift, do not change size. Change depth. A fly sitting lower, or right down in the film, solves it more often than a new pattern does.