It’s common for river and lake fishermen to use over-sized baits come fall, a time when bass, walleyes and other warmwater gamefish are eating the larger prey available at this time of year.

So why shouldn’t the same philosophy apply to stream anglers pursing trout? According to noted fly angler Tom Ference, it does.

“My yardstick is that I go as big as I feel the trout in that particular creek are willing to eat,” he said. “And that’s usually a lot bigger than most people think.”

Traditional streamer patterns like the Mickey Finn and Black-nosed Dace typically mimic a minnow in the two- to three-inch range. Ference, however, prefers to cast longer flies, ones more representative of the size minnows bullish stream trout feed on in the cooling water of autumn.

As such, Ference uses streamers in the three- to six-inch range, tied on No. 4 or No. 2 hooks. Though throwing a big streamer on a fly rod is a challenge, Ference feels the effort is worth it, theorizing that his odds are better showing the fish a bait that best represents the size of the prey they prefer to eat now.

Traditional streamer patterns are often limited in length by the natural size of the materials used to create them. To attain more lengthy streamers, Tom uses ostrich herl, which comes in lengths up to six inches and is available in many colors.

When water conditions are fairly clear, as they were during an outing last week, he sticks with drab colors such as brown and olive. He will incorporate some contrasting color to the fly such as yellow or orange.

The length of the fly may get a trout’s attention, but it’s the action imparted by the angler that turns lookers into strikers. Tom feels part of the secret of effectively fishing magnum-sized streamers lies in the way they are presented.

“I want the trout seeing the streamer to feel that it’s a minnow, and that it’s obtainable,” he said. “Meaning I want it to look alive, but I want it to look injured as well.”

To do this, after he has completed his cast he allows the fly to sink for a few seconds. Then he begins working it back toward himself, pulling line with his free hand, and imparting rod tip twitches, to do so.

“I want enough speed to get the trout’s attention, but not so much that it thinks the bait is too challenging,” he explained. “I want the fly to look like a big, easy meal.”

Adding a bit of weight to the fly is often a necessary evil. It makes the already unwieldy fly even more difficult to throw. But pegging a small split shot above the fly also gives it an up-and-down jigging action, something the trout often respond to.

“Adding some weight right at the nose of the fly allows the ostrich herl plumage to really pulsate when you impart those twitches,” he explained. “Rather than using a floating line, you can use a sink-tip line and a shorter leader, which makes casting easier. But doing so does deaden the action a tad.”

When using streamers, Ference likes to fish “every piece of water that he thinks could hold a trout,” as he puts it. So he covers the water, hitting both moving water and the slow stuff. While he might bypass a gravel-strewn shallow shoreline areas during mid day, he’ll hit it early and late in the day, when he feels feeding trout might move up on it.

“If the water is deep enough to hold a trout, I want to present that streamer to the spot,” he said. “Generally it only takes three of four casts. So I keep moving.”

Ference recommends an eight-and-half foot fly rod for handling big streamers, one designed to cast a 5- or 6-weight line. When fishing larger streams or rivers he’ll go up to a 7-weight rod. Leaders run to 7.5 feet, with a six-pound test tippet.

Jeff Knapp is an outdoors columnist for the Butler Eagle