One of my best dry fly fishing days was a couple years ago on the South Fork of the Boise River. The next fall I returned to the same spot, same time of the year and almost scored zero with the same dry patterns. The fish were still there and so were the same insect fare, but the fish were keying on another stage of the hatch. I got fish, but the takes were somewhat reluctant, like I'd pestered the fish long enough so they took my dry just to get rid of a nuisance. They were not much interested in the dun - the pre-emergent active nymph, the emerger or even the spinner had their interest.
In a given day of hatch activity, all four stages present themselves to the fish in strong enough numbers to lock their feeding activity on one stage. It struck me at that moment on the Boise that I had allowed myself to get locked on a stage that was not effective. It dawned on me at that moment that an accomplished fly fisher would accept the challenge to fish all stages of a particular hatch. On a given day on a given river it would be a real
accomplishment and discipline to successfully fish each stage of the hatch from nymph to spinner. I switched to a soft hackle emerger and immediately was into a fish. When the emergent stage is identified as the predominant stage then all sorts of patterns come into play, including even traditional nymph patterns fished just under the surface. This is very subtle -surface fishing with takes almost as visible as those with a high floating dry. Even more subtle are the gentle sipping of spinners off the surface film. I hadn't fished. a spinner in years so I tried one just for fun and also got into fish. So in a few casts on the same river I got fish on all parts of the cycle except the pre-emergent nymph. It took a real slow day with dries to get me to switch but hopefully I won't be so reluctant next time, for each phase has its own brand of challenge and enjoyment.
I guess the challenge I accepted that day was to not get locked in on
a particular phase of the hatch. Sometimes on the Green River I would
avoid the particular hatch altogether and just stay with the always productive
scud, or cicada or whatever.
I think we are enriched by our sport if we are able to adapt our fly selection to the appropriate phase of the hatch cycle and move with the fish from one cycle to another. The dun or dry fly phase is usually preferred by most fly fisherman for the pleasure derived from being able to observe the float of the fly and the take. But this stage is probably the least preferred of the fish because of the energy expended to capture the insect at its least vulnerable moment. The gentle swirl or flash of the take of the emerger or the almost imperceptible sip of the spinner are the poetry of our experience.