I don't love writing "how to" posts but if there is an area of fly fishing I am pretty experienced with, it is fishing terrestrials. So this is my attempt at a "how to" post about fishing terrestrials - a rather timely topic.
If I had to pick a month of days that represent the best fishing in the Driftless Area, it would be from April 15th to 20th or whenever the Grannoms (Trichoptera (caddis), Brachycentrus) start hatching for the next 30 days into mid-May. This is the "buggiest" time of the year and trout become much more surface oriented during this time. Yeah, they are still eating a lot of nymphs and scuds and they will continue to smack streamers but this is the time each year I morph back into a dry fly snob.
However, if I had to pick a month of days to fish for pure enjoyment and often a great challenge; it would be from mid-August through mid-September. I catch more fish in the mid-April to mid-May time frame but I catch larger and tougher fish in late summer. And I see fewer anglers than earlier in the year, a very nice bonus.
Late summer and early fall fishing is not easy. The fishes have been educated by anglers for seven months or more by now and some of the more gullible of their ranks have met the creel. The weeds - both in the stream and along it - are up and make for smaller casting lanes, more stuff to accidentally hook, and on smaller streams, there is not as much exposed water. While it varies from year to year, mid-summer streams are often low and at times, too warm which limits where to fish. In comparison, unless the water is very high, pretty much every mile of designated trout streams are fishable and really at their peak in mid-April through mid-May. This all adds up for challenging but rewarding late summer fly fishing.
Maybe this is going too far but any idiot can catch a trout in April and May but by August, you have to be a bit more on your game. Without question, there are some exceptions to that statement. We have all had days where any grasshopper looking thing that hit the water gets crushed and the fishing is pretty easy. However most of the time, late summer trout do not come easily. Typically, if you want to fish hoppers - and do well with them - you need to be where the hopper are which means in the thick grasses. I fished one of my favorite hopper spots today (not today but the day I wrote this...) and it was a slog to walk downstream through the thick prairie to get to where I wanted to start fishing. It was not an easy to walk continuously grazed pasture nor was there a well trampled trail. But that is all part of what makes it such a good spot. Upcoming is a bit what to look for and what terrestrials to fish where.
Terrestrial Taxa and What to Look For
Grasshoppers get most of the glory - mostly because they are so fun to fish. When fish are on hoppers - as they were yesterday (which I referred to as today above - confusing, ain't it?) - the "eats" are splashy and violent. That is the fun of hopper fishing and it is awesome when it is like that. But, of course, those are the memorable days - the average day is often much tougher.
As the name suggests grasshopper like and live in grass (no, really!) so I look for prairies and rotational grazed pastures. What I am looking for in a spot to fish hoppers is really thick grass. My favorite spots are tough to walk through and when you do walk through them, you should be kicking up hoppers with ever step. There are places were you hear them by the hundreds. If the hoppers are not jumping in front of you, that is a sign that something other than a hopper might be a good better choice. Lastly, look at those hoppers and get a decent picture of how large they are. I think anglers are often doing two things wrong on choosing sizes; 1) fail to start small and get larger as the season goes on as the real thing does and 2) using hoppers that are too large compared to the naturals they are imitating. I don't think trout get overly picky about fly pattern but I think there is some advantage to fishing flies that are about the same size as the majority of the naturals.
In late-summer, if at all possible, I have a hopper or an attractor that looks "hooper-ish" - Chernobyl, stimulator, Hippie Stomper, etc. - tied on. When I say this, I am talking about from 9 or 10 AM - grasshoppers are cold blooded and need some sun energy to be mobile - until near dark. Early in the morning and late in the day, there are often better options which you have certainly noticed as you have walked through grasses as these times and noticed almost no hoppers moving. I find that many anglers marry themselves to fishing hoppers when there are better options for when and where they are fishing. I will dig a bit into other options for times and places.
Beetles are generally my "not much is happening but I want to fish a dry fly" choice of flies. And Andrew Grillos' Hippie Stomper probably is taken as a beetle much of the time - but who knows. Beetles are the most diverse taxa of animals on Earth, representing 25% of all known animal species. Why this matters is that they come in all shapes and sizes and in nearly all habitats. There are even a number of aquatic species such as the riffle beetle (family Elmidae).
My gut feeling is that they are rarely numerous at any one time but trout are familiar with them due to their ubiquity and overall numbers. The exception may be on days with a decent breeze, around trees, when they quite often hit the water. I have sat and watched trout repeatedly rise to beetles on a windy day in the location of the above photo. The willow beetles - for lack of a taxonomic name - are often small and nearly round beetles. Trout will feed on them with little hesitation but the cast and drift to get at them is not simple - and forget wading in that loon crap!
Beetles are a great choice for when you want to fish dry but nothing in particular is happening. Compared to grasshoppers, their season is much longer. By mid-April, beetles are active and they will remain so until the end of the season. And beetles are everywhere so they are a great all-purpose searching fly. I like them more around trees but they are plenty numerous in grass and shrub-lands. Your standard issue foam beetle will work great and can be tied on a longer shank hook for a more elongate beetle and on a short shank for the more rounded beetle. Tie a few of each size and shape and I pretty much also add something to increase visibility. Want something more natural, the Crowe Beetle is a great choice and you can easily add a little sighter to it.
Ants are everywhere and there is more biomass of ants in the world than there is of humans. In fact, ants are thought to be 15-25% of the Earth's terrestrial animal biomass and it takes an awful lot of ants to make one elephant's worth of biomass! I find ants anywhere and everywhere. Generally the best spots are trees and shrubs along the stream but they are also common in grasslands. Like beetles, they are a great searching pattern because they are everywhere all the time.
I like ants as a general searching pattern, a fly to target tough fish, and often for a "hatch buster". Like beetles, ants work well from before the frying pan opener though the end of the season. If there is an issue with ant fly patterns, it is that they are often hard to see on the water. Parachutes or patterns with built in visibility are very useful. Ants range in size from really small - #20 and smaller - to the larger carpenter ants which may be as large as a #10 or #12. Most of the time, a realistic size is a #16 or #18. Of course a few fly patterns have the name ant in the name - Chernobyl Ant, Bionic Ant - are really as much attractor / searching dry flies as they are ant patterns.
I find that with ants, maybe more than any other terrestrial type, casting needs to be on the spot. Ants rarely fall far from the stream edge unless that are in an overhanging tree. Maybe the best terrestrial fishing I have ever happened across is when flying ants are hitting the water. It is a pretty rare occurrence but when you hit it, you are in store for some of the craziest fishing you will ever experience. Trout go nuts for flying ants and will hit them with gusto. I have a story in the works for another post about the disappointment that was New Mexico's San Juan River tailwaters where the fishing was too easy. The largest trout I have ever hooked into was a beast of a Brown Trout on Pennsylvania's Big Fishing Creek in probably no more than 6 or 8 inches of water that hit an ant under a tree.
Crickets are generally overlooked but are my ace-in-the-hole. I tie the low rider or simply "My Cricket" (yeah, it needs a better name) that I posted in the Driftless baker's dozen flies post that is probably as much a beetle as it is a cricket but it is my go-to when fishing is tough - like in shallow glides in mid-summer. I will also tie and fish a Morrish cricket using the smaller size cutters.
In my experience, crickets tend to be found in places with some bare ground. By far the place I am fishing cricket imitations most often are in continuously grazed pastures where there is little vegetation that the cows have not managed to graze down to the ground. On days when fish are not chasing hoppers, I may first switch to a cricket and see if that works better. Often this is on overcast days. Hoppers seem to need a little warmth and sun to get their bodies warm enough to be active. Crickets don't seem to have that same restriction. I find that fish often smash hoppers while crickets are eaten more slowly and deliberately. Give them a try - I think too many anglers fail to give them a chance.
By the middle of summer, terrestrial insects are what are available to trout as food. Aquatic insect production is very low and there are decreasing hatches. And at that, the hatch most associated with summer are the Tricos not so affectionately referred to as the "white-winged black curse" by some fly anglers. Terrestrials are where it is at once summer starts.
Like all animals, terrestrial insects have specific habitats where they do best. Sure, ants and beetles are pretty ubiquitous but even they are more numerous and dependable in some places compared to others. Want really good hopper fishing? You probably have to get into the thick stuff. Sure, you can fish hoppers through a continuously grazed pasture and maybe you will catch some fish but it is not the ideal place to fish them. Ants and beetles are everywhere but generally you will see them be more important around trees and shrubs. And the poor overlooked crickets tend to be where there is some open ground. Think of your experiences and where you have seen the different terrestrial insects and use that to your advantage.
Some time ago I wrote about the River Continuum Concept (RCC), probably the single most important idea in stream ecology. The RCC predicts physical and biological changes as we move from the headwaters downstream to a stream's mouth. In smaller streams, allochthonous inputs - like terrestrial insects - are very important and as streams get larger, their importance decreases. I like small streams where terrestrial insects can be find anywhere in the stream channel. Moving to a large stream like the one above and you need to "pound the banks".
Lastly, a bit about ideal conditions...without question, the best days for fishing terrestrial fly patterns have a little wind / breeze. On dead still days, you are at the mercy of their clumsiness but on breezy days, you will see a several fold increase in the number of bugs hitting the water. If I could get a fairly warm but partially cloudy to overcast day, I would certainly take that to help hide me a bit better. The nice thing about fishing terrestrial patterns is that the window is pretty large. I am fishing ants and beetles from at least May through the end of the season while crickets and hoppers have a bit of a shorter window but still several months long. And over the course of a day, terrestrials may not be an early or late in the day choice but they will work over most of the daylight hours.
I have written no shortage of posts about terrestrials or related ideas and am linking them below.
Optimal Foraging Theory and Fly Fishing (IMHO, this is the most important post I've written for fly anglers).