A parachute Blue-winged Olive dry (upper right inset) is a good choice to duplicate the Baetis dun (far upper right) that batches each fall on the Missouri River. Rainbow trout (lower left inset) and nonspawning browns take advantage of what may be the Missouri's last big batch of the season–autumn Olives. (E. Neale Streeks photos; rainbow trout inset Barry & Cathy Beck photo)
October 10, 2022
By E. Neale Streeks
Editor's note: Flyfisherman.com will periodically be posting articles written and published before the Internet, from the Fly Fisherman magazine print archives. The wit and wisdom from legendary fly-fishing writers like Ernest Schwiebert, Gary LaFontaine, Lefty Kreh, Robert Traver, Al Caucci & Bob Nastasi, Vince Marinaro, Doug Swisher & Carl Richards, Nick Lyons, and many more deserve a second life. These articles are reprinted here exactly as published in their day and may contain information, philosophies, or language that reveals a different time and age. This should be used for historical purposes only.
This article originally appeared in the December 1988 issue of Fly Fisherman magazine. Click here for a PDF of the print version of "Autumn Olives."
Autumn in Montana finds most anglers hunkered down in a riffle, fishing streamers with big rods for spawning browns. Naked cottonwood limbs rattle overhead in a cool breeze. Pheasants cackle from the brush. The subdued browns, golds, and grays of the highlands are accented by a fresh dusting of snow.
A stoic angler stands hunched forward, applying with gloved hands a death grip to the cork handle of his rod, hoping for that arm-wrenching jolt of a trophy brown trout. A 5-pounder would be nice, but a double-digit, hook-jawed male is a more realistic trophy. It's work, but sometimes it pays off. Catch rates are low-similar to steelhead fishing, and as with steelhead, many of the big fish are taken off their spawning beds.
But during autumn, at the tailouts of big riffles and at the edges of the weed-lined banks, something else goes on. One of the season's most predictable hatches is under way, ignored by the few anglers on the river. It is midafternoon, and the autumn Blue-winged Olives–Baetis –ride the rich, green currents. Trout rise everywhere, even near the streamer fisherman's feet.
Afternoon Olives Every afternoon, from just after lunch until near darkness, Olives can be found hatching, tumbling on the surface, sailing with the breezes, and whirling in eddies. Every afternoon rainbows and nonspawning browns feed on them. During October and November, when the browns are spawning, Baetis drift on the water. Again in spring-April and May-Olives hatch, providing the dry-fly fisherman with sport.
More than a dozen species of Baetis hatch on Western waters, but their similarity allows imitation with just a few simple patterns. The duns range from #16 to #20, with olive, olive-brown, or gray being the primary colors. The fly's large blue-gray wings are highly visible and are probably major keying factors for the trout. Baetis are found in many types of water, especially shallow riffles and the trailing weedbeds found in rich alkaline rivers. These are common habitats in the broad Missouri River. Two and even three broods of Baetis a year are usual with this genus, with spring and fall hatches common. The Baetis hatches are among the most prevalent and important hatches on many rich Western rivers.
The nymphs are active swimmers, darting several inches with a single thrust. They feed on organic matter collected from the surface of rocks and weedbeds. The color of the nymphs ranges from cream to olive to brown, with pronounced, dark wing pads. Just before a hatch, nymphs become restless and active, and nymph fishing at such times can be productive.
On the cool days of autumn, before flying, Olive duns usually drift several feet on the surface, sometimes much farther, giving trout ample opportunity to feed on them. Baetis often show a preference for overcast days and subdued light, but they do hatch in brighter sunlight, preferring the warmest time of day-midafternoon. Even during a light rain you can find good numbers of Olives on the water. Under these conditions the insects are slow to take wing. When you are fishing, it's important to target risers one at a time, perhaps drifting your fly over the fish's nose several times before he takes. The trout may have a steady rise rhythm that must be timed correctly, so try to present your fly just as he drifts up to take another natural. Fishable Olive spinner falls are rare. Western Baetis spinner falls occur in early morning or late evening-tim.es when most fishermen are not normally on the water. Further complicating the spinner fishing is the fact that some females dive or crawl into the water to lay their eggs, making them difficult to see.
Traditional fly patterns such as the Adams and Blue-winged Olive imitations, along with thorax and parachute imitations, work well during Baetis hatches.
Compara-duns, emergers, and nymphs also take their share of fish. These flies, in sizes 16 and 18, should reflect the color and size of the natural (see the accompanying sidebar for suggested fly patterns). When fishing from a boat in deep, swift water, use attractor patterns and larger flies. Adams, Coachmen, H & L Variants, Irresistibles, and similar flies in sizes 12 to 16 draw strikes when used in cliffside pools, deep riprap runs, and other water where the fish are opportunistic feeders that don't have the luxury of inspecting a fly closely before deciding to take or refuse it.
Matching Tackle to the Water The Missouri's water is clear but filled with nutrients and living organisms that give the river its deep-green hue. I use from 9- to 12-foot leaders and from 4X to 6X tippets when fishing the Olive hatch, depending on the stillness of the water. The slower the water the longer and finer the leader and tippet I use.
While there isa place here for short, light rods, especially for wading and stalking closely, longer rods work best. The mending, distance, and wind-casting capabilities of a 9-footer make it the best rod length, and it can also be a safer rod for fishing from a boat. On a calm day, however, I enjoy using a light 7-footer while wading. 'Use as much backing as possible on your reel. You'll need it for the searing runs and numerous leaps of the rainbows.
On the Missouri, a boat is handy to get to the less pressured spots. This big, fickle river is difficult to read, and a guide provides valuable advice. The Missouri is a complex fishery, with different types of water adjacent to each other. For instance, there are places where you can find deep, swift-flowing pools on one side of the river and shallow, slow, weedy water on the opposite side. The trout in these different types of water behave differently. You can alternate dry-fly fishing of the afternoon Olive hatch with morning and evening streamer fishing for big browns and rainbows, capitalizing on the best of both worlds. With only two fishermen in my drift boat, I use the stern for a rod caddy. I rig one light rod for close wading with match-the-hatch drys, and a longer rod for fishing larger drys from the boat. Another large rod with a sinking-tip line has a large, weighted streamer tied to its tippet. Having these three rigs saves time and leader material when I switch tactics.
Wadeable Flats I usually wade-fish the wadeable flats, which include inside bends, shallow riffles, tailouts, smaller eddies, side channels, sloughs, and edgewacers. Patchy weedbeds offer better cover for the fish than a totally clean gravel bottom. Trout are picky in these areas. Thick, difficult-to-wade weedbeds often harbor the most selective trout. Most of the flats have gravel bottoms that are easily wadeable, with spotty weed growth and prime areas for stalking rising fish.
Giant swirling eddies the size of small ponds can hold dozens of trout. Many of the rainbows in this water rise continually, and they are less selective due to the wide variety of foods and floating debris that collects in the eddies. I have often seen trout singly and in groups, cruising the open water or lurking beneath the cover of overhanging willows and cliff walls. You need a boat to fish most of these spots, and you can spend hours drifting around them, picking off risers throughout the day.
Riprap banks built in railroad and highway construction have countless swift, deep-water lies, and those overgrown with willows provide exceptional lies for fish. The trout in such places take drys well when surface feeding, and slightly larger patterns such as# 12 to #16 Adams, Irresistibles, and Royal Wulffs often work well on fish that must make a hasty decision about eating the insects that quickly pass by in this fast-flowing water. In addition, the willows hold a great number of different insects that fall or are blown into the water, and the fish that hold nearby are accustomed to seeing a wide variety of food float past. The Adams, Irresistible, and Wulff patterns look like many different insects, making them productive in these waters. When boat fishing on cloudy days, however, casting large streamers into the riprap can produce large fish. Large browns can be aggressive on such overcast days, lunging from their rocky cover to grab viciously at your fly. The days that browns are really on the prowl (as opposed to nights) are few and exciting. Taking advantage of overcast weather for both streamer and dry-fly fishing can reward you with truly memorable days.
Finding Feeders Spotting risers can be more difficult on big rivers than on a stream, especially in wind and in glaring or low-light situations. However, you should seek out the largest trout, casting only to sighted fish. You will see hundreds of risers from 8 to 14 inches long. Try to spot the 14- to 22-inchers, after discriminating them from the thousands of Missouri River whitefish. Trout may also congregate in giant eddy lines and riffled drop-offs. Although there may be 50 trout rising steadily in the riffled surface, they can be difficult to spot under poor light conditions or if you have poor eyesight.
Large fish like this rainbow (main) feed on Baetis duns (inset) with a quiet rise, instead of the showy porpoising rise you might expect to see during a heavy hatch. (E. Neale Streeks photos) Many large, rising trout hold in the quiet edgewaters, out of the main force of the current and along bankside weed clusters. These edgewaters aren't necessarily the deep outside bends (the typical holding positions in small rivers and streams), although such places do support many trout. Large Missouri River trout rise near shallow, weed-laced, inside bends, side channels, riffles, drop-offs, and tailout flats that are easily waded during Baetis hatches. Many of these unexpectedly shallow lies hold large trout that make wakes as they bolt in fright from careless waders. Take your time to slowly wade and search. It's the way to spot the large rising trout. Because many trout and whitefish often rise together to afternoon Olives, you should use your time judiciously, identifying the largest trout and presenting your Olive imitation drag-free over his nose.
How to Spot Big Trout Look for the largest, slowest wakes following a sipping rise. On the Missouri, trout tend to sip, not porpoise as they do on rivers such as the Bighorn. The larger and slower the wake the larger the trout, although some large trout show little surface disturbance when they are in a shallow-depth feeding position where they don't have to move their bodies much to take floating insects. Head risers are common in faster water-riffles, drop-offs, and eddy lines. If you observe carefully, you should see the top of the trout's head as he pushes forward to take a fly. He makes a wedge-shaped rise form, and he tends to feed steadily. There are swift-water flats on the Missouri with so many head risers feeding at once that the water appears to be riffled. Fishermen with poor eyesight or lack of experience never see the heads. They mistake them for riffles.
Whitefish tend to school, preferring shallow to moderate-depth, gravel-bottom runs and pools. I say tend, because whitefish can be found almost anywhere in the stream, and some whitefish do excellent imitations of trout behavior. As I mentioned, Missouri rainbows usually sip or head rise-they don't porpoise. When you see a dorsal fin or tail above the surface, it's usually a whitefish feeding in slow water. In faster, deeper water whitefish make a small splash as they take insects, and their tail breaks the surface when they dive back for bottom. Trout hover, cruise, and sip. When you see a cluster of these little splashes, you can assume them to be either whitefish or juvenile trout. In slow, shallow water whitefish often porpoise in groups or singly, exposing their fins.
Look for trout at the perimeters of whitefish schools. Whitefish and trout sometimes feed together. Whitefish are often more selective than trout when feeding on a hatch of smaller flies. Often an oversize imitation causes a trout to charge up through a school of whitefish. The whitefish are more particular and avoid the imitation. Again, when approaching a running pool with its dozens of risers, look for the quietest yet largest wakes following a sipping rise, especially at the feeding lanes closest to banks or weedbeds.
Knee-deep in the weedy flats waters, I watch for risers. The cool afternoon breeze carries the scent of stubbled hayfields. The Belt Mountains's volcanic cores–weathered into magnificent spires, walls, dikes, and monoliths–soar above the great fertile valley. The leaves and swallows of summer are gone.
On the river's ruffled surface, tiny floating Olives sail and twist in the currents. Trout rise near a willow-hung bank protected from the breeze. A plump rainbow sips the season's last mayflies as they collect in the calm, currentless edgewater. I lay my fly gently on the water above him. White mouth agape, he drifts up to sip it in. I strike and miss. With a mighty boil he is gone to the cover of midriver.
Oh well, I may find him again, perhaps when the Olives and swallows return in springtime.
Olives for Trout Blue-winged olives is a common name that applies to more than a single mayfly species. Although Baetis , which range in size from #14 to #24, are thought of most often when fishermen talk about Olives, the Pseudocloeon species, such as anoka and eamundsi are also generally classified as Olives. But because of their size (#20-#28), Pseudocloeon are sometimes called Tiny Blue-winged Olives. With Baetis and Pseudocloeon overlapping in the size range from #20 to #24, this is a perfect example of the confusion caused when common names are used to identify similar but different species. For more detailed information about the various Olive species, refer to Selective Trout, by Doug Swisher and Carl Richards (published by Nick Lyons Books, New York), and Hatches II, by Al Caucci and Bob Nastasi (published by Winchester Press, Piscataway, New Jersey). These books are available from book stores, fly shops, mail-order fly tackle dealers, and The Angler's Art, P.O. Box 148F, Plainfield, PA 17081.
(E. Neale Streeks photos) A few simple patterns will suffice for matching Olive hatches, but remember to determine which insect is coming off and choose your fly accordingly.
Baetis NymphHOOK: #14 to #24, Mustad 9671.THREAD: Brown, size 6/0.TAILS: Mallard flank fibers dyed olive-brown.ABDOMEN: Medium to dark olive-brown rabbit fur.WING CASE: Dark brown or black quill strip.THORAX: Same as abdomen.LEGS (Optional): Brown soft hackle, grouse or partridge.Adams HOOK: #14 to #24, standard dry-fly model.THREAD: Black, 6/0.TAILS: Combination of brown and grizzly hackle barbules.ABDOMEN: Gray muskrat-fur dubbing.WINGS: Grizzly hackle tips.HACKLE: One grizzly, one brown dry-fly hackle.Baetis Compara-dun HOOK: #14 to #24, Mustad 94833 or equivalent.THREAD: Olive, 6/0.TAILS: Dark gray, dry-fly hackle barbules or spade hackle.BODY: Olive-brown dubbing with a slight yellow cast.WING: Medium to dark gray, fine-textured deer hair.Baetis Spinner HOOK: #14 to #24, Mustad 94833 or equivalent.THREAD: Olive, 6/0.TAILS: Gray hackle barbules, split.BODY: Medium tO dark olive-brown rabbit-fur dubbing.WINGS: Light gray hen-hackle tips, tied spent.Pseudocloeon Nymph HOOK: #20 to #28, dry-fly model, Mustad 94842 or equivalent.THREAD: Olive, 6/0.TAILS: Light olive hackle barbules.BODY: Fine greenish-olive dubbing.LEGS: Olive-green hackle fibers.NOTE: A dry-fly hook is used because of the small size of this nymph. Use your favorite nymph hook if it is available in #20 through #28.Swisher/Richards Pseudocloeon Dun HOOK: #20 to #28, dry-fly model, Mustad 94842 or equivalent.THREAD: Olive, 6/0.TAILS: Light gray hackle barbules.BODY: Fine greenish-olive dubbing.WINGS: Light gray hen-hackle fibers, tied as a clump.HACKLE: None, or light gray hackle tied parachute-style with only two wraps of hackle.Pseudocloeon Spinner HOOK: #20 to #28, dry-fly model, Mustad 94842 or equivalent.THREAD: Olive, 6/0.BODY: Blend of olive, light brown, and orange rabbit-fur dubbing.WINGS: Light gray hen-hackle tips, tied spent.E. Neale Streeks, a Missouri River guide, lives in Great Falls, Montana.
This article originally appeared in the December 1988 issue of Fly Fisherman magazine.
