The Western Spruce Month Fly Fishing Blitz

The West’s New Spruce Moth Blitz
NOTE: This article previously appeared in Fly Fisherman Magazine. Thought you still might glean some valuable information from these words. If I remember correctly, some people were pissed to see the spruce moth hatch being touted in print. They came after me hard, some saying the hatch didn’t exist and others saying I shouldn’t have said  a word about it. To each their own. By printing it again, here, you know how I feel about the subject. Read up and get out there. greg

There are few hatch secrets in the West anymore and the best of the big bug action – the salmonfly, green drake and red quill hatches – have been flogged to death … in the literature and on the stream.

Secretly, what we dream of in the West these days is a trip back to the 1950s and 1960s when there were fewer people on the water and the hatches were left open for interpretation and discovery, including the delightful and rewarding construction of new fly patterns to best match them.

I thought that dream was just that, a dream, until I slipped into southwest Montana’s Big Hole River and found butterfly-style bugs falling out of the trees and gorgeous brown and rainbow trout smashing the hell out of them.
It was two years ago, mid-August, a time when hatches are few and the Rockies’ trout have been fished hard for three or four months, a time when trout can be most difficult and wary. I looked upstream and down, and took in a visual mile – there wasn’t another angler to be seen.

In every direction, hundreds of those odd bugs could be seen in the air. Those that fell to the water were immediately slammed. And every time I cast a fly – and I mean every time – a good trout rose to my offering within the first three feet of the drift. Some fish left their feeding lanes and plowed four or five feet through shallow water to bang the fly, the ultimate in trout fishing visuals.

That those bugs, which turned out to be Western spruce moths, were present on the Big Hole in such abundance arrived as a surprise because a few years back, in the late-1980s extending through the 1990s, spruce moths were almost nonexistent on the Big Hole and many other streams in the West where they were traditionally found. In fact, throughout their range, which begins in British Columbia and Alberta, Canada and runs south through Washington, Oregon, Idaho, Montana, Wyoming, Utah, Colorado, New Mexico and Arizona, spruce moth populations were almost nonexistent after having been measured at infestation levels during the 1960s, 1970s and 1980s. Some blamed the decline on natural conditions, namely freezing temperatures during spring, while others pointed a finger at control measures applied by the U.S. Forest Service.

Fortunately, during the early 2000s the spruce moth, which is often called the western spruce budworm and carries the official title Choristoneura occidentalis, made a comeback. Entomologists, including Ken Gibson at the U.S. Forest Service’s northern region headquarters in Missoula, Mont., aren’t quite sure what influences the cyclical nature of spruce moths, but there’s little doubt that weather is a major impact and that conditions, right now and for the foreseeable future, must be close to ideal.

“Spruce budworms work on a one-year lifecycle,” Gibson said. “The eggs are deposited in the tops of trees in August. By September the immature larvae hatch. They don’t feed during winter, they just spend their time in a silken case. In the early spring, just as the buds are developing and expanding, the larvae leave their cases and bore into the buds or feed on foliage.

“They feed until the early part of July,” Gibson added, “and then they pupate from the larval stage to the adult. That happens over a two-week period. During a warm year that may happen earlier, during a cold year it may happen later. Typically, they are ready to fly in early August. When they fly they search for mates, mate and then deposit eggs to start the cycle over.

“Right now populations have rebounded from the late frosts we saw in the 1990s and they are really high,” Gibson added. “Our aerial surveys show a million acres of defoliation in western Montana alone. It will take a while for the budworm’s parasites to build so I expect the population of spruce moths to be high for at least the next seven or eight years and possibly much longer than that.”
Some of the well-known waters where anglers are again finding spruce moths include the aforementioned Big Hole, as well as the Madison, the Gallatin, Rock Creek, the Yellowstone, the St. Joe, Kelly Creek, the Clearwater, the Lochsa, the Selway, the Middle Fork Salmon, the Yakima, and the West Fork Bitterroot. Be sure, the spruce moth is found on additional waters ranging from large streams to the tiny, forested tributaries of major rivers tucked back into spare corners of the West, including some roadless lands that beg to be explored.
In fact, if there’s a major western insect blitz that could be overlooked, the spruce moth hatch is it. Think about it: the hatch is short-lived and it’s been mostly forgotten for 10 years or more; it’s geographically limited on the streams where it occurs; it arrives at a time (the dog days of summer) when guided angling pressure is limited at best; and it’s safe to imagine that many fingers of larger rivers carry the hatch and are overlooked by anglers targeting the well-known sections and documented hatches. One could easily discover and hide a secret hatch for years.

For example, when inquiring about spruce moth activity in Colorado I learned that the bug is present through most of western Colorado, it also has a presence along the Front Range, and it was most active during 2006 in southern Colorado, specifically in La Plata, Las Animas, and Huerfano counties. It’s affecting timber in the Gunnison, Rio Grande, Routt, San Isabel and San Juan national forests. But, could I find one angler or outfitter that knew if that activity has translated to fishing opportunity? The answer is no. But that should spark interest – a full late summer, in fact many late summers, could be spent prospecting for an untouched hatch. The same could occur in Utah, Wyoming, New Mexico and Arizona, where the bug isn’t as abundant as it is in Idaho and Montana, but it is present.

The revival of spruce moths in the West is significant because, in the opinion of this writer and many other spruce moth devotees, the hatch is one of the best western angling options of the year, if not the best of them all. In comparison to some of the Rockies most noted hatches spruce moths are smaller than salmonflies and they don’t elicit the same kind of fly fishing buzz that the Pteronarcys emergence brings, but they come off during a time of the year when angling pressure is modest and water conditions are at their predictable best – this hatch won’t be lost to poor water conditions. In addition, spruce moths may not be as pretty as green drakes, but they come off in bigger numbers and again, water quality issues aren’t a concern. In comparison to the west’s major early-season caddis hatches, there may not be as many bugs in the air when spruce moths come off, but the bugs are bigger and more predictable than those caddis and the trout are bigger and in better shape during late summer than anglers find them in the spring. And, again, water conditions really don’t affect the quality of the spruce moth hatch as they might during the early caddis action when rivers are as likely to run the color and consistency of chocolate milk as they are to run see-to-the-bottom clear. In addition, when compared to a massive western Trico hatch, which is also present in late August, the spruce moth blitz may not be as impressive numbers-wise but, when fishing spruce moth imitations, anglers don’t spend five minutes trying to thread 6X tippet through the eye of some miniscule size-22 hook and once they get a fly attached to their tippet, anglers matching the spruce moth actually can see their fly on the water.

However, the spruce moth hatch doesn’t arrive without limitations. First, the hatch usually comes off during the dog-days of August when daytime temperatures may elevate to the 90-degree Fahrenheit range or higher. Also, the hatch isn’t long-lived, meaning it typically starts by the first week in August, builds through the middle weeks of the month, and dies out before the end of the month. (Do note: depending on air temperatures and elevation, the hatch may begin as early as early-July and extend as late as late-September) In addition, the hatch is typically restricted to the morning hours, meaning it begins around eight or nine, just as the sun tops the mountains and brings warmth to the air and extends until noon or 1 p.m. when the heat really builds and the hatch often dies. Finally, during a hot summer, emergency angling restrictions may be placed on some of the streams where spruce moths are found.

As mentioned, the typical spruce moth day begins between eight and nine in the morning as the air temperature rises and the moths gain energy. As soon as they are warm, they rise out of the trees and begin searching for mates, first a few, quickly dozens, followed by hundreds or thousands depending on the quality of the location. Spruce moths are strong flyers but they are not immune to wind. In the Rockies, the summer wind typically picks up around 9 or 10 a.m. and it deposits lots of weak flyers onto the water. The trout take notice, quickly moving from their dark hiding places – around rocks, under logs, in the deeper pools and runs – into prime, unobstructed feeding lanes often in shallow water, meaning fewer than four-feet deep and sometimes in water just deep enough to cover a fish’s back. If a Trico spinnerfall is in progress, as it often is at that time of the day during August, the fish may quickly switch away from those diminutive mayflies and focus their attention on moths. When the hatch is on, don’t overlook midstream runs that may appear as too shallow and clear to hold fish. Believe me, the fish lose their typically wary minds during the hatch and they frequent some unusual places. In addition, look for fish along rocky banks where depth and cover offer a sense of security. No matter where you choose to throw a cast, rarely are you focused on a particular fish, trying to time your offering with its next rise. Just cover water with an attractor dry or a specific moth imitation.

During the early stages of the hatch the fish are gluttonous and they attack basic attractor dry flies, such as size-12 and size-14 Goddard and Elk-Hair caddis. Occasionally, in their haste to devour a moth, a trout may miss an angler’s offering the first time, possibly even the second time, and return a third time to waylay their victim. If a fish misses your offering, don’t worry that you may have jerked the fly away and created a commotion. Sometimes that’s the best thing you could do because that’s exactly the way natural moths act as they try to escape the death-tug of the surface film.

As the hatch progresses toward noon or 1 p.m., the trout, now somewhat gorged, may get picky. Often, anglers may be required to change flies and twist on a specific spruce moth imitation, such as the late Gary LaFontaine’s Spruce Moth, a heavily tested pattern that proved its merit on western Montana’s Rock Creek. However, often brief delays in the action are ended by a strong gust of wind which may blow many more moths out of the trees and onto the water when begins another frantic round of feeding.

At some point, however, the hatch subsides and the fish return to their picky, late-summer routines. At that time downsizing your fly may solicit a few more takes, as does downsizing the diameter of your tippet. Early on in the hatch 4X tippet is fine (you might even get away with 3X tippet), but later in the hatch going to 5X tippet may be required.

Another tactic during the later stages of a moth hatch is to bypass picky fish, trout that you may be able to see in the water, holding a foot or two under the surface or occasionally rising, but can’t coax to the surface. Or, a fish may rise toward your fly but repeatedly resist the temptation. Sometimes the best thing to do is say, “you win” to those types of fish and just move on to a more willing customer.

Anyone who experiences a solid spruce moth event is a fortunate soul and those who fail to take advantage of the current upswing in moths, especially in Montana and Idaho, are really missing out. In fact, Doug Persico, who runs Rock Creek Fisherman’s Mercantile in western Montana, thinks that sin is worse if said angler is a dry fly fisherman.

“I think that a guy who passes up a chance to fish the spruce moth is passing on one of the great experiences in angling,” he warned. “If you are a dry fly fisherman it doesn’t get any better. It beats the salmonfly hatch and it even beats my dearly beloved spring March brown hatch. The weather is great, the fish are eager, and they love the spruce moth. Even the big fish will come up for it so you get the best of it all – big fish and lots of fish and you get to throw a size-12 fly. It turns the dog days of summer into an adventure. God, it’s a great hatch.”

Ennion Williams, manager of Lone Mountain Ranch in Big Sky, Montana, has guided anglers during the spruce moth hatch for three or four years. He agrees with Persico – it’s not a hatch to be missed.

“It always came off around the beginning of August, but now it’s beginning in July and lasting longer,” he noted. “The patterns we use are the Stimulator or a light-bodied Elk-Hair, size 10 or size 12. The fish do get picky with those later in the hatch. You can change flies or tweak them to create a crippled version or you can sink them.

“There’s no nymphal stage to the spruce moth, but the fish will eat drowned moths under the surface,” Williams added, “and that’s what we do a lot. But, really, it’s pretty easy fishing and on the Gallatin it’s been a massive hatch for the last few years and it brings up some of the largest fish. It just takes over during a time of the year that used to be pretty slow.”
That’s the way it is these days on the Big Hole, too, and while standing in that river last year, I couldn’t help but consider my fortune when the moths started out of the trees.

The skies were blue and the morning was crisp enough to offer a shot of energy, but not cold enough to say that summer was nearing its end and that fall would arrive anytime soon. In addition, there were only a few anglers on the water, spread over miles of prime stream. In essence, I had the river to myself on the kind of beautiful day that makes you forget all that seems unfair in life and lets you believe, if only momentarily, that you’re the richest person on Earth, as good days on the water tend to do, no matter where you cast a line.
A half-hour later I had landed a half-dozen or more fish, including an 18-inch brown that broke my four-weight rod. I raced to the truck, swapped out the rod and was back on the water 10 minutes later to find the river just alive with trout. Every cast drew a rise and some of those fish were the types you’d burn a roll of film on. The action was so good you almost had to laugh, but at the same time you soaked it up and took advantage of the opportunity because in the back of my mind were all those memories of fishless days when the hatches didn’t come off, or the water conditions weren’t right, or the weather chased you off the water early, or there were just too many people, or the fish were just too plain stubborn. If you’ve fished out west more than a couple days of your life, you know what type of frustration I’m talking about. Which brings up this point: nobody, really, knows how long the current spruce moth infestation will last. So get out there and take advantage while the taking is good.

I suppose, in the end, that the value of the spruce moth hatch – any super productive hatch, for that matter – is a chance to see western trout at their best and to be able to tempt large fish to the dry fly. That’s the spruce moth hatch, a late-summer bonus for those anglers who are fortunate enough to find it.

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