Mid- to late-August is a great time to be out fishing in Colorado. We start the change from summer to fall and these "dog days" of August that can be so hot are the time to fish some bigger terrestrial patterns. While dry fly action is no doubt still an option -- Red Quill patterns and Tricos come to mind -- fishing an ant or hopper can entice big fish with the promise of a protein-rich meal.
Amy's Ant in the rivers and small streams of Colorado has been a go-to fly these past two summers. A red Amy's Ant has been productive at Deckers, Elevenmile Canyon, and on smaller streams like Beaver Creek and Chalk Creek. Fish it against the bank and be ready on the first cast because fish will hit it aggressively. Wary Rainbow and Brown trout will also play with your head sometimes by rising and batting the fly with their tail. They may just be checking to see if the offering is real -- but it's entertaining, frustrating and amusing to have a handful of strikes in a good pool as the fish "play with their food." Be patient, move upstream a little to change the angle of presentation, and work your way from bank to middle of the water for some strikes.
Large hoppers offer another protein-rich meal for aggressive strikes. Kirk Deeter over on www.fieldandstream.com describes hoppers as the juicy double-cheeseburger of patterns. One of the keys of fishing a hopper is to be able to imitate a real one when it is in the water. Hoppers are big bugs ... and big things sink! Try working the hopper at different depths. Sink it just a little bit by using some split shot or use some sinking grease to drop it sub-surface.
Dropping small nymphs off of large foam Ant and Hopper patterns increases the chances to take a fish. Managing the depth of the nymph is always one of the challenges for a hopper-dropper rig. Start deeper -- sometimes the difference between a good day and a great day is a matter of inches -- and then you can work your way up by trimming off some of the tippet between the hopper and the nymph. Be sure the hopper is big enough to stay afloat when you tie on a nymph. Nothing worse than casting out and seeing your hopper sink!
Terrestrials and late-summer fishing are a natural match. As with other patterns, though, varying conditions affect how productive terrestrials may be. In Colorado, we have just finished a very heavy monsoon season. Colorado's Department of Agriculture reports that the grasshopper count in Colorado may be down from previous years. But don't tell the fish that. Just present a nice meal near that opposite bank.
Orvis 101 Introduction to Fly Fishing
Orvis 201 Streamside