Old timers around here refer to this as "the hatch", as if it is the only one. The salmonfly hatch on the Madison is the biggest thing that happens in the natural world on this river, in any given year. The bugs, the birds, the fish, the fisherman; it's just a bonanza in the natural world.
The hatch goes on for 3+ weeks and progresses upstream several miles a day. The bugs live in the bushes for five to seven days.
There's a little bit of art, a little bit of science and a little bit of total voodoo when it comes to fishing the big dry fly.
Being in the right place at the right time is certainly part of it. The tactics once you're there are key: which fly you're using, how you're fishing it, where you're putting it.
One of the most important things in fishing this hatch is reading water and really knowing what kind of water the fish hold in. For example, I never see fish eating the salmonfly dry in the big slicks of the big rock. You can fish little caddis there and some other attractors and get fish up there, but that's not a spot where they rise typically to your number four dry stone.
A common mistake is mending your fly and it skates down and across and out of the spot. If you can manage your line in such a way that you can create skitter... What I call upstream skitter, that's what sells it to them. That is the higher art of fishing the salmonfly on the Madison.
Really give that bug some action. When you see those naturals land on the water, they don't just lay there lifeless, they throw a fit and swim to the bank. Big trout, that are five, six, seven years old have been to the rodeo a time or two. How many salmonflies do they see in the average season? Hundreds, if not thousands. You've got to be there at the right moment sell it to them.