A few of the big yellow mayflies began to show, struggling at the surface of the dark water then, drying their wings, breaking free and flying.

I switched to a graphite rod on which I had tied a 3X leader and a big yellow parachute Hex imitation. My friend Craig Schuhmann handed me a Floating Hex Nymph originated by the late Klamath tyer Dick Winter. I knotted a length of tippet material and fished the two flies in tandem.

Late June and early July mark one of the great bug events on the Williamson River when that largest of the mayflies, the Hexegenia, throw their shadows on the water. If the Hex hatch happens at all, it happens at dusk.

A tributary of Upper Klamath Lake, the Williamson River drains about 3,000 square miles of southeast Oregon. Connected to the food-rich lake, the trout migrate out to feed and then back to cool off in summer.

A 5-mile float offers time for reflection. We watched trains pass, the cars flashing by on the tracks, mirrored in the river. One image in my mind is a four-pound rainbow three feet above the surface, its red-banded body reflected in the water it has just burst out of at the moment the fly came out of its lip.

In the last hour, trout boiled along each bank. We cast to rise rings. In a summer evening punctuated by 21 grabs and a dozen battles and five fish brought to my hand, the hatch was a frantic moment between dusk and full dark when we measured casts, lost track of our flies and struck at sounds and splashes.

Fishing the hex hatch

The hexegenia hatch on the Williamson River might be the most well known, but in June and July, the big bugs can pop on Clear Lake, Lost Lake, Timothy Lake and Harriett Lake on the slopes of Mount Hood. The biggest hex hatch I ever witnessed was on a summer evening on Clear Lake when the rocks were yellow with bugs and the fish plucked dries lazily off the surface.

Carry two rods, one loaded with a floating line and the other with a sinking line and a 3X tippet. The dry is best matched by a No. 10-12 yellow Hex Paradrake or an Extended Body Hexagenia.

The best fishing can be on substantial nymphs like the Red Fox Squirrel Nymph, Beadhead Wet Hare’s Ear Wet or Dick Winter’s Floating Hex Nymph. Fish two nymphs in tandem at first, then switch over to a dry with a floating nymph in tandem.

Green drake

Look at the calendar. If it says May at the top, an angler should be ready to match a green drake hatch at any moment. It’s a short window of opportunity, but it’s the most important thing happening that week in the eyes of Drunella grandis and Oncorhynchus mykiss gairdneri (the redband rainbow).

Coincident with the more well publicized salmonfly hatch on the Deschutes River, green drake mayflies start to appear in May. By June some trout will pass up a bigger stonefly to chase down a green drake. Green drakes may be more prevalent on the Metolius River in May and June and a second hatch happens on the Metolius in September and October.

The green drake is a sporadic hatch on most western streams, but it can be abundant on the Metolius and a few others. It is a good idea to carry dries to match this mayfly when the adults could show up any time.

Best bets include the Loop Wing Green Drake, Electric Green Drake and the CDC Green Drake Emerger.

Callibaetis

The most reliable mayfly hatch to follow is the Callibaetis which shows up in May on rivers like the Owyhee and the Powder and is important in the mountains from Anthony Lakes to East Lake and Paulina through the end of August.

Once I saw so many callibaetis in Diamond Lake, I thought they would hold me up if I fell out of the boat. The trout as fat as footballs were so sated we had to switch to different flies to get them to eat.

One morning in July at Anthony Lake, I caught 23 trout in two hours on a Callibaetis Nymph in tandem with a Rubber-legged Hare’s Ear. Some of my favorite imitations include Dexter’s Callibaetis (tied with wood duck and red fox) and Dexter’s Pheasant Callibaetis tied with natural pheasant, red Flashabou and rockchuck fur.

One of my new favorite dries is Mason’s Mighty Morsel Mayfly (from Rainy’s Flies) which takes a traditional design and adds a foam saddle for buoyancy, a poly wing and a short sub tail imitative of a nymphal shuck. The fly comes in six different variations: Adams, blue-winged olive, pale morning dun, purple, March brown and Callibaetis.

May, June, July and August, these are the months of the mayfly. If we are honest, this is why we fly fish, for the moments when the trout crash through the surface tension to eat the fly. And the reflections in between.