Early Autumn, September to be exact, a time of year when the low flows of late summer begin to turn the warm water temperatures towards a cooling trend creating a unique opportunity to pull the biggest trout in the river to the surface to eat. The low water of late summer equated to high river temperatures for trout to endure. However with the onset of cool nights as we transition to fall, the river temperature begins to fall into a more desirable range. The drop in water temperature causes an increase in trout activity. The previously lethargic trout caused by the warm water temperatures are now actively feeding. Using large bodied foam flies to tempt the biggest trout is easily achieved with the correct approach.
Dwindling numbers of adult bugs flying around and hatching in the river causes a competition for food. Trout will set up on active feeding lanes looking to bulk up for the winter and the coinciding low food season. While a trout is actively feeding on small insects in a repetitive process the importance of large food sources cannot be overstated. The importance of these terrestrial insects becomes apparent in how far a fish will leave a desirable feeding lane to eat a grasshopper or ant.
Terrestrials are a category of insects that are important to fly anglers for their ability to draw powerful surface strikes. Examples of terrestrial insects commonly found in the watershed are grasshoppers, crickets, ants and beetles. As large protein food sources, trout will move considerable distances to eat one. When a trout eats a bankside grasshopper that inadvertently fell upon the water, the reaction is no joke. The resulting strike is meant to kill the hopper at the same time as the fish eats the bug. Trout do not like anything struggling in their gullet. Kicking hoppers and large winged Stoneflies are devoured so that they have no opportunity to struggle. Large food sources such as terrestrials and other food sources like crayfish are eaten with authority and power. Other prime choices for terrestrials would include the Elderberry beetles, stoneflies around the full moon and cicadas.
Brown trout develop an aggression that drives their desire to feed. This pre-spawn aggression is apparent in their ability to cannibalize young brown trout and any yellow and brown streamer that happens to swing their way. Combine this aggressive feeding behavior with a compressed water column and you have the components for a crushing surface bite. The feeding party doesn’t just revolve around brown trout. Rainbow trout are commonly found set up along bankside vegetation and under bubble lines actively feeding on the surface. When the water column is compressed by a low water situation, a dry fly on the surface is still within the striking distance of a trout holding at the bottom of the river. A dry fly presented in July floats feet above trout, whereas now the dry fly is within easy reach and often results in reactionary strikes.
Heavy bank-side vegetation is a prime situation where insects like terrestrials become desired food sources. Terrestrials are unique because they don’t live in the watershed or have a life cycle revolving around water. Willows growing along the river often drop grasshoppers and ants onto the water especially during our windy afternoons. Trout recognize this large food source is prevalent at this time of year. Consequently, they will seek out areas where they can take advantage of these higher protein insects. When it comes to comparisons one grasshopper equals the protein equivalent of a pile of midges and requires less energy less to obtain.
The energy necessary to feed in a moving current eating size 20 midges must burn more calories than the little midges provide. However a grasshopper the size of my pinky finger provides the sustenance for a fat bellied trout to have some disposable weight during the lean winter months. Find a feeding trout eating tiny BWOs in a feeding lane and watch him not hesitate to swim over for a grasshopper that fell on the surface.
Mastering Messy Presentation
Fly choices for low water conditions in the Fall season often contain a lot of foam. High riding and with the ability to uphold a heavy dropper in the ever popular Hopper-Dropper, rigging foam flies slide across the surface with an enticing allure. Rubber legs dance seductively with each ripple giving the suggestion of a struggling insect. As an active bug when it falls into the water, a grasshopper allows the angler to fish the fly sloppy. This means it can land hard and loudly, it can squirm and wiggle, it can be stripped across the surface like the kicking stroke of an adult Grasshopper.
Large foam bodied grasshopper patterns in colors to match the local insects provide the basis for a fun day. Observe the insects bank-side or on your walk down to the river and use them as the template for the size and color you want to mimic. Umpqua’s Realistic Foam Hopper rides in the surface film like a real grasshopper. Match the color and size to your local hoppers and hold on!
Foam Ants are a local favorite for our rivers too. Some patterns are very visible for the angler with high riding foam as the main component and brightly colored tags for visibility. Once again rubber legs have the ability to look alive and move with the slightest movement or ripple. Amy’s Ant is a popular selection for an ant imitation. Hippy Stompers, Carl’s Foam Flying Ant and the Hi-Vis Beetle all from Umpqua provide an excellent selection of foam-bodied flies to use during the low water condition of September.
Low water and big foam flies. Autumn is an ideal time to tempt the largest trout up to the surface to eat. Terrestrial insects cause quite a commotion when fished in the shallow water column. Whether used in a Hopper-Dropper presentation or as a single dry fly on the surface, give it a try. Big foam bugs have a special place in any fly angler’s box. Vail Valley Anglers has all the Umpqua foam flies you need to take advantage of the stellar dry fly fishing Fall possesses.
Michael Salomone, Fly Fishing Guide & Content Writer