For sportsmen, fall means opening day and stalking elk through the Colorado back country. The decrease in anglers (and football on the tube) generally lead to less crowds, but just because there are fewer people fishing, the fish are still there for the taking! As the weather cools, bugs and insects don't hatch as often as in the spring or summer. Making fall fly fishing a little more difficult, but that doesn't mean the fishing has stopped. Brown trout and kokanee salmon spawn in the fall and are moving to find the best place to make their redds,
Because of this, fishing where feeder streams and tributaries confluence with larger streams is a good place to look as trout will be moving into these areas to spawn. "While we never advocate fly fishing for actively spawning fish that are on shallow gravel redds, these tributaries allow anglers to predict where to find larger fish," according to Vail Valley Anglers. "Fish in deeper water that aren’t on beds are fair game and with a quick, gentle release they will be free to continue their mission to propagate the species. Be aware some small tributaries are closed during the spawn because the trout are simply too vulnerable in these tiny creeks."
Trout will also start to develop predictable eating patters when the summer hatches dwindle down. With fall approaching, the blue wing olive mayflies and midges are now the primary food source. Under the right circumstances, trout will still feed heavily as they prepare for the colder, winter months ahead.
With blue wing olives as the primary food source, blue wing fly patterns are a primary "go-to" for fall anglers. But according to Vail Valley Anglers, size is more important than pattern, "Flies mimicking these bugs (BWO) should range from #18-24. This is more important than the actual fly pattern. Choose flies in olive or grey such as the trusty Parachute Adams, Sparkle RS-2, CDC Loop Wing Emerger or JuJu Baetis."
But going smaller isn't always the best, especially if you're after the monster brown trout. As the brown trout are moving around looking to spawn and are becoming more territorial, using larger streamers may help you catch the largest fish.