Mayflies and Fickle Trout

Sending the trout free.

There’s something about mayflies that get flyfishers excited. If you look at the flies displayed in any fly shop, chances are that the majority of flies are intended to resemble a mayfly in one or another phase of the mayfly’s ephemeral life (pun intended).

Some years ago, I had a chance to fish on Michigan ‘s Au Sable River during the Hex hatch, meaning the giant Hexagenia Limbata mayfly, and tied up some flies that were an equivalent to the Salmonfly of our western rivers. Actually, I once had a streamside conversation with an angler from Michigan who, with some buddies, came out to Montana in mid-June to fish the Big Hole River’s salmonfly hatch. They didn’t bring any giant stonefly imitations so just used their Hex imitations and reported, “The trout liked them just fine.”

Near the other end of the mayfly spectrum of the Hexagenia is the little spring mayfly called Blue Wing Olive, or simply Baetis for those of us who like to impress people with a little Latin. They’re not the smallest of our mayflies. That title goes to the Trichorythodes, or tricos, of late summer. 

The baetis mayfly calls for a small fly, from a size 14 to a tiny size 20. I use mainly size 16 dry fly hooks for my imitations, and that’s what I was using on, appropriately, the first day of May, when I was knee deep in the lower Madison River in the Beartrap Canyon. When I went in the river I didn’t see any bugs on the water, so I started casting a nymph, imitating the juvenile phase of the mayfly. That didn’t get any takers, but I started to see some adult mayflies floating down the current, and then I started to see some dimples on the water, indicating that trout also noticed the adult mayflies and were picking them off the water’s surface.

Of course, knowing that fish are feeding is no guarantee that they’ll take a fly. I tied on a dry fly that, to me at least, looked like the real thing. Trout are, of course, the authority as to what looks like food, so I tried several variations on imitation mayflies. The one that brought some attention was a relatively sparse Sparkle Dun, a fly with a deer hair wing and no hackle.

After some refusals, I had a take from a trout that was rising just three feet from me, and when it felt the hook it tore off across the river. It took a few minutes, but I finally led it into the shallows where I was able to slip the hook from the fish’s jaw and let it swim away. I didn’t measure it, but it was a beautiful rainbow trout, around 15-inches.

And, as it turned out, that was the only fish I caught in a long weekend of camping and fishing on the river. In four days of fishing, those few rises on May 1 were the only rises I’d seen. We had one day of hot weather that I thought would result in an explosion of the Mother’s Day Caddis, but it didn’t turn out that way. Caddisflies were mostly absent.

Clouds from the leading edge of a cold front coming in.

A cold front came in that evening, bringing some welcome rain, but that also turned off the fishing. 

Kiri posting for another dog on a rock photo.

If the fishing was slow for the most part, the weekend was a good way to start our camping season. Hot, high winds on one day were annoying, but anyone who fishes the Madison River knows better than to be surprised when it’s windy. The real surprises are those days when it isn’t windy.

While the weekend marked the beginning of the summer camping season on the Lower Madison BLM campgrounds, it was standing room only, as far as late arrivals hoping to find vacant campsites. 

Last year, in the first year of the Pandemic, Americans re-discovered the great outdoors. As we begin to emerge from the shutdowns, it’s reassuring that the outdoors is still important, at least here in Montana.

Paul Vang’s new book, “Golden Years, Golden Hours,” is available at How Novel, The Second Edition, Isle of Books & Books, or online at

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