The Importance of Fly Fishing Scouting Missions

This article was originally titled "Scouting Mission" in the Feb-Mar 2021 issue of Fly Fisherman magazine.

For most fly fishers, the joy of catching a fish is amplified when it comes as a result of careful planning and preparation. Don’t get me wrong—accidental fish are always welcome. But when you plan for it, tie specific flies for it, visualize it, and everything comes together, those are accomplishments we cherish forever.

One of those memories started for me one November day when a friend and I embarked on a scouting mission. Water flows were at 60 cubic feet per second (cfs), with water temperatures hovering around 46 degrees. We did not expect great numbers of fish because of the low, cold water, but to battle the cold-weather blues we decided, “Let’s give it a shot and see what we can learn.”

Over the years, I’ve found that days with low expectations can produce big rewards, but sometimes you have to be patient to earn the payoff.

Things started slowly as expected, but to our surprise, later that afternoon the water flows bumped up. Typically, when you have increasing flows, debris and vegetation along the edges are swept into the river, and the water loses clarity and gains color. Fish that hide under, around, or near structure in clear water begin to come out and actively feed on dislodged food items like leeches, insects, and crustaceans.

We located something in front of a large boulder in a run that was now about 6 feet deep. It was so big and colorful it reminded me of a “floater” giant redfish from the marsh in Louisiana, but it was actually a massive trout. We devised a plan for a proper presentation. I kept my eye on the trout for my buddy, and he changed flies and varied his weight and his leader length for more than an hour. To our utter disappointment, this fish simply would not take anything we offered. We were both guides on a day off, but we couldn’t catch this particular fish. Little did I know that this humbling experience was also a learning experience. It was the type of scouting mission that an elk hunter might do, checking an area days or weeks before hunting season.

A few days later I had a guide trip with my client Justin Cohen. The day started like any other sunny early winter day. I expected a good midge hatch, and actively feeding trout, but nothing extraordinary. The South Platte in the winter tends to be low and clear, but once again, about an hour into the trip the water turned off color, and clumps of vegetation drifted down in the rising current. I instantly thought of the fish we had spotted previously in these same conditions, so we hiked in that direction and found the same brown trout in front of the very same boulders. This time I saw the trout swaying back and forth, an indication the fish was feeding heavily. Given the rising water conditions, we thought a Mini Jig Leech was a good idea.

After a few casts, we saw the fish turn and track the leech, but refuse at the last moment. Since the fish at least seemed interested, we made a minor adjustment from a black to a rust leech. On the second cast the fish turned and took the fly, and Justin set the hook.

All hell broke loose as the fish rolled at the surface, splashing water 10 feet in two directions. I knew right away that this could be the largest trout I’ve ever seen in this river. The battle continued downriver for 150 yards, and close to six minutes later I was finally able to slide the trout into the net headfirst. We measured this giant at 35.75 inches long with a 20-inch girth. Those measurements put it just shy of 20 pounds. My previous “failure” had turned into the opportunity of a lifetime for Justin.

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Sunny Skies

In conditions with clear water and sunny skies, it can be difficult to catch trout because they are spooky and wary. Turning bright days into scouting missions helps you study the contours of the river bottom so you can be more effective on cloudy days, evenings, or even night forays.

When dealing with bluebird skies, I start looking at deep runs and probing the depths to see how much weight I need, and how long the leader should be to reach the bottom.

I also use the sun to scan the water flowing around or under structure, deep pockets, and in eddies. These are all zones where trout can hide in bright light, and then actively feed when light conditions change or a hatch comes off.

In addition to scoping target-rich areas, map out where the best location is to make a cast and where to present your flies. For example, if I’m on a high bank looking down into the deep run with sunny conditions, and I notice a rainbow or brown trout holding in front of a boulder, I make a note about which angle is the best to make a drift without snagging anything underwater. That way I have a visual map of what the run looks like.

Structure provides opportunities for trout to feel safe, and also ambush their prey. My favorite structure types are boulders, and natural woody debris like logs along the edge or both instream and on the edges. Sometimes boulders trap drifting logs so you get both together. These structures provide easy places for trout to hold, and there’s often swifter current nearby where they can grab food. The changing current speed also helps obscure the trout, and because of the increased current flow around these edges, there are often deep spots where trout feel secure. Instream vegetation growth is another thing under which trout can hide, like the safety of a blanket that oftentimes is packed with food.

Even if you can’t see trout in these places, look for signs. The gravel on the bottom of the river or lake is often dirty or covered in silt or algae. When a trout’s tail sweeps like a broom over these locations, it cleans the sand dirt and gravel, creating long streaks where the fish has a tendency to swim up- or down-river. It’s like looking for footprints when scouting for elk. These spots sometimes show where the fish comes out to feed, or the pathway they take through the weed beds to get to their favorite feeding station.

Night Shift

Scouting during the day creates opportunities for you to come back to these same places in late evening or after dark. Please don’t fish at night in the seasons when trout are actively spawning. Brown trout in particular use the cover of darkness to spawn in the shallows, so you shouldn’t be out there wading around and disturbing them.

Summer is the best time for night fishing, as the daytime sun and heat cause big trout to become nearly dormant in the day and look for bigger prey items at night. Do your night hunting under a full moon or naturally bright starry sky. This allows you a better opportunity to see where you are casting, and trout use the light of the moon to hunt. Have you ever noticed how lousy the fishing can be during the day when the moon is full or nearly full? It’s because the big trout are feeding at night.

Don’t use bright headlamps to fish at night. Use the light of the moon or a headlamp with a red light to tie knots. You can also use a luminescent fly line like the Scientific Anglers Amplitude Smooth Infinity Glow to make more accurate casts, but as during the daytime, don’t “line” the fish.

Sometimes night can be a scouting mission as well, when you see and hear big trout feeding at certain places at night but can’t catch them. The same fish are likely nearby during the day, and the light might help you hone your strategy a little bit. Every session on the water should be counted as research for future outings.

Window Shopping

On cloudy days trout feed more because there tend to be more hatches of aquatic insects, and they feel more secure from the danger of predators from above. Ospreys have trouble spotting trout in cloudy, dark conditions—unfortunately, so do we. However, birds of prey do not have polarized glasses, and I don’t believe they can anticipate “windows” in the surface currents like a stationary fly fisher can.

To see into these windows, you’ve got to position yourself to reduce glare across an entire viewing lane, and then watch slicker windows of smoother water as they move downstream. To use these windows effectively, peer through them as they move. Use your vision to scan along the bottom. It doesn’t work as well to just stare at one spot and catch a glimpse as the window passes by.

You can use these windows on stillwater as well, when wind creates chop on the water. The trout are more inclined to feed in shallower areas with this type of chop on the water. This gives you a chance to scout the edges of lakes and reservoirs—places that might be barren in calm, sunny conditions.

Searching Flies

You will spook fish every day you are on the water. When I see that I’ve spooked a fish, I make a visual and mental note about exactly where the fish was sitting. Then after an hour or two, or at the end of the day in low light, or a few days later, I go back to that spot and fish it cautiously and more strategically. I can’t tell you how many times I’ve turned a spooked fish into a fish in the net.

The types of flies you use can also be an important part of your scouting mission. In prime conditions with insects hatching, we all love to match the hatch for best results. For me on the South Platte, that often means using very small flies that imitate midges and tiny Blue-winged Olives. But on days when nothing is hatching, and the fish don’t seem to be feeding, you have to get innovative to get the attention of large predatory fish. This usually means using larger searching patterns.

Kelly Galloup’s Tips Up Streamer has two foam heads tied on the trailing rear hook. This fly causes a lot of commotion when you move it. Whenever you pause the retrieve, the tail rises and sways in the current. This is the exact movement of a crayfish fleeing backwards. I like to strip two or three times quickly with a pause to mimic the natural food supply.

Charlie Craven’s Double Gonga represents many types of baitfish and gives you the options of light and dark color variations. I use an exaggerated pause during the retrieve to make it look like an injured swimming fish, and give predators an easy view of the side of the fly whenever possible.

With large streamers, and particularly in low water, you’ll produce a lot of reactions from the fish, but not always hook-ups. If a fish bolts from the fly, make a mental note, just as you would with any other spooked fish (see above). You’ll also notice that big fish often chase streamers in a territorial response, but then don’t commit to eating. Sometimes these fish have alarmed themselves and become hyperaware. In other instances, they’ve shown they aren’t in a feeding mood, they were just chasing the smaller invader from their space. However, sometimes you can downsize to a fly that is less threatening and catch a fish that has revealed its position.

When you are considering searching fly patterns for your scouting missions, think about patterns that imitate multiple food sources. You don’t know what the fish are feeding on, or if they are feeding at all, so give yourself as many chances as possible to spark a reaction.

Davy Wotton’s Muddler Daddy fits this ideal, since it looks like a lot of things but nothing in particular. “The Muddler Daddy was created to imitate the large crane flies that are helplessly wind-blown across the lakes and reservoirs whenever these is a wind,” says Wotton. “It also resembles many different terrestrial insects, as well as small sculpins and crawdads. The Daddy is usually fished as the top dropper of a team of flies and fished by what we call dribbling, working the fly on and off the surface as you retrieve the team of flies back toward you in the traditional loch style.”

Jack Dennis’s Amy’s Ant represents a stonefly, hopper, or cicada. It can be skated, twitched, or dead-drifted on the surface and in the surface film. Because it matches such a large variety of food items, it is an attention grabber. I slap the dry fly down aggressively, and often twitch the fly intentionally by mending the line. I wrote about this technique in my article “Stand Out in a Crowd” in the June-July 2017 issue of Fly Fisherman. Since then, I have learned that when you are playing peek-a-boo with large trout, a great way to trigger a strike is to downsize the dry, so I start with a #8-10 Amy’s Ant, and if I get a refusal I can switch to #12-14 or even #16 and convince the trout to actually eat the fly.

My Mini Leech Jig Damsel represents multiple food sources and works in both stillwaters and in rivers. It can be used as part of a double nymph rig, or as a dropper below a dry fly that imitates another food supply. My favorite method is to have a Goddard Caddis dry fly with an olive or tan Mini Leech Jig Damsel dropped about 18 to 24 inches below. You can skate and twitch the Goddard Caddis on the surface, and when you do you’re also bringing the Mini Leech Jig Damsel to life. 

It’s a double attractor rig, and often fish come to investigate the skating caddis, then end up eating the Mini Leech Jig Damsel below. It’s also a great part of a deep nymph rig because the slim build and tungsten bead help it get down quickly. Even when nothing is hatching, leeches and damsels are always around, and trout have a hard time saying no to these types of large opportunistic meals.

These searching flies will help you get a reaction from trout on days when nothing is hatching, but you want to make the most of your day on the water. They also help you learn where the fish are holding, because they “wake up” dormant trout.

Be aware of the trout that refuse the fly, the trout you spook while exploring, and use your time on the water to watch and observe. I truly believe you can become a better fly fisher without even casting, just by practicing and enhancing your powers of observation. Use those low-water days, those bluebird sunny days, and those no-hatch days to carefully study the places trout might be hiding. Look for a hint of color, the slight movement of a tail, or a shadow. Make a note of what you see, and try some new flies and new strategies to coax a trout into a reaction. The things you learn today can pay big dividends down the road.

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Landon Mayer is a Colorado fly-fishing guide and Fly Fisherman contributing editor. He lives with his wife Michelle and their four children in Florissant, Colorado. His most recent book is The Hunt for Giant Trout: 25 Best Places in the United States to Catch a Trophy (Stackpole Books, 2018).