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Fly Tier's Bench: How to Tie Dorsey's Top Secret Baetis Fly

A tiny fly packed with decades of experience.

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I have known Pat Dorsey for more than 30 years. I am as surprised as anyone that I have yet to write an article about one of his flies. “Dorsey” is a household name in the Colorado fly-fishing industry, and with good reason. His guiding skills are legendary, and he still puts in over 200 days a year on Colorado’s South Platte River and surrounding waters. Dorsey is a spectacular guide and has an uncanny ability to spot fish and coach his anglers into catching them. He has authored several books including the definitive Fly Fishing Guide to the South Platte River (Stackpole, 2018), has written numerous magazine articles in this publication, and has been a Fly Fisherman field editor for nearly two decades. His longevity is a testament to his skill, but also his personality and work ethic. I have always been a huge fan and consider him a good friend, so it is my honor to finally feature one of his many fly patterns here on the Fly Tier’s Bench.

Pat Dorsey started guiding in Colorado right about the same time I did, and I recall the first few times I saw him on the river. He was always bent at the waist, peering intently into the river with one finger pointing at the fish, as he directed his clients where to cast. He always had a big goofy smile on his face. It’s clear he loves his job, and he’s damn good at it.

As a former guide myself, I can tell you that while Dorsey is one of the true gentlemen in the game, as well as one of the nicest people you’ll ever meet, you definitely don’t want to be guiding behind him. The guy just doesn’t miss much. There were days where I felt like I was fishing barren water until I finally hopped in front of him. I think there may have been days when he slowed up his pace a bit just to give me a chance, and I always appreciated it.

The pattern that I’ll feature here is Dorsey’s new Top Secret Baetis. Based off the success of his remarkable Top Secret Midge pattern, Pat has taken a familiar route to alter the pattern slightly and create an accurate Baetis imitation. It is possibly the best blue-winged olive fly going.

The beauty of this fly is that it is tied from very commonly available materials—for the most part, albeit with some necessary modern-day substitutions—and it is very easy to tie which is nice from a guide perspective when you get home at 9 o’clock at night and have to whip up a dozen more for tomorrow.

Dorsey starts with a Tiemco 2488 hook as the chassis for this new pattern. This is a wide-gap, short-shank hook that creates a small fly with great hooking power. This hook has become the go-to for many small-fly aficionados for exactly this reason. Pat uses beautifully mottled Hungarian partridge body feathers for both the tail and the legs. While it’s not the most durable material in the world, it’s awfully hard to argue with the beautiful speckling and mottling of these feathers.

The Danville 6/0 olive tying thread is actually more of a tobacco brown. It forms the abdomen, with a small black UTC wire rib to create segmentation.

The wingcase throws a hitch in everything. Dorsey, being a long-term commercial tier, undoubtedly has a lifetime supply of the now unavailable Medallion Sheeting from the late Shane Stalcup stashed away in his tying room. While Pat opted to use this maerial for the wingcase on his Top Secret Baetis, it is no longer available for the rest of us. I use gray Swiss straw as an alternative to get as close as possible. I must admit, I was planning on teasing Dorsey here about being a materials hoarder until I looked through my own stash and found a whole bag of Medallion Sheeting of my own. I guess great minds really do think alike.


The thorax of this fly is simply dark olive/brown dubbing. I prefer Superfine for flies like this as it dubs down tightly and holds its shape well, but any variety of fine dubbing will work in this application.

Dorsey likes to fish the Top Secret Baetis in a two-fly rig under an indicator. He has become famous over the years for his yarn indicator system. He uses a rubber band to make this sensitive indicator more easily adjustable. In the spring and fall he frequently fishes a Top Secret Baetis with a Top Secret Midge on a dropper to cover the bases of the most commonly available food sources.

From a fly-tying perspective, I can appreciate how quick and simple this fly is while having it still check the box of a fly that I would want to fish. These days there are so many reasonably simple fly patterns that work well but have no soul or appeal to fly tiers. Dorsey took a simple combination of materials and created a fly that is durable, quick and fun to tie, and it not only gets the job done, but it also looks good doing it.

Recommended


Note: I bought my Dyna-King Pro in 1990 and have tied more than 1,000,000 flies on it since then. That vise came from the shop of  Ron Abby in Cloverdale, California. In 2023, Mayfly Outdoors—the same company that owns Abel, Ross, and Airflo—purchased Dyna-King. Now the precision machining, customer service, and sales all now all take place through the Mayfly Outdoors factory in Montrose, Colorado. It’s the same place Abel reels are machined.

I tied this fly on the Dyna-King Professional, which has four different tying angles you can lock into place, as well as 360-degree rotation.

Dorsey’s Top Secret Baetis Recipe

A fly in a vise.
Dorsey's Top Secret Baetis nymph.

Step-by-Step Instructions for Tying Dorsey’s Top Secret Baetis

  1. Start the tying thread about an eye length behind the eye (index point) and wrap a single-layer thread base to just past the bend of the hook. Select a nicely mottled partridge feather and strip the fluff from the base. Draw out six to eight fibers from the stem until their tips become even and peel them from the stem.
A step-by-step image of tying a fly.
Step 1.
  1. Tie this clump of evened fibers in at the end of the thread base, forming a tail that is about a half a shank length long. Wrap forward over the butt ends to just behind the start of the thread and clip the excess.
A step-by-step image of tying a fly.
Step 2.
  1. Tie in a length of black wire at the front of the thread base and wrap back over it to the base of the tail. Use the tying thread to build a slightly tapered abdomen, taking care to keep it smooth and thin.
A step-by-step image of tying a fly.
Step 3.
  1. Spiral wrap the wire forward to the front of the abdomen and tie it off with a few firm thread wraps. Helicopter the end of the wire to break off the excess. Overlap the tying thread over the front edge of the abdomen to the 60% point on the shank. Cut a strip of Medallion Sheeting that is about half as wide as the hook gap.
A step-by-step image of tying a fly.
Step 4.
  1. Apply a thin layer of tight dubbing to the thread and build an oval thorax, making sure to leave about an eye length of bare hook shank behind the hook eye.
topsecretbaetis-5
Step 5.
  1. Draw another clump of fibers out from the stem of the partridge feather, this time using about twice as many as you did for the tail. Make sure to even the tips and peel them from the stem of the feather maintaining their alignment. Use the tips of your scissors to divide the bunch in half.
A step-by-step image of tying a fly.
Step 6.
  1. Place the divided fibers on either side of the hook shank just in front of the abdomen. Measure the tips so they extend back to the hook barb. I cant the fibers slightly toward me to accommodate the twist of the thread torque when I tie them down.
A step-by-step image of tying a fly.
Step 7.
  1. Transfer the measured fibers in place to your material hand and pinch them tightly against the hook.
A step-by-step image of tying a fly.
Step 8.
  1. Make a loose wrap of thread over the partridge fibers just in front of your fingertips and allow the thread torque to pull the near side up and far side down, aligning the fibers with their respective sides of the hook. Make a few more tight wraps over the butts to anchor the legs.
A step-by-step image of tying a fly.
Step 9.
  1. Lift the butt ends of the partridge fibers and draw them back over the top of the fly as you make a couple of turns of thread to anchor them. Folding the fibers back like this will make for a smoother head area and hide the butt ends under the wingcase rather than leaving their rough edges exposed at the hook eye. After the fold and wraps, clip the excess fibers as close as you can.
A step-by-step image of tying a fly.
Step 10.
  1. Leave your thread hanging at the back of the index point and fold the Medallion Sheeting wingcase forward over the thorax. Capture the wingcase with a pair of tight thread turns.
A step-by-step image of tying a fly.
Step 11.
  1. Now pull the long end of the wingcase back over the top of the fly just like you did with the butt ends of the partridge and cinch it in place with a couple more thread wraps. Again, this fold eliminates a stub end that will crowd the hook eye on the finished fly.
A step-by-step image of tying a fly.
Step 12.
  1. Build a smooth thread head with your whip-finish and clip the thread. Trim the excess wingcase material as closely as possible.
A step-by-step image of tying a fly.
Step 13.

Charlie Craven co-owns Charlie’s Fly Box in Arvada, Colorado. He is the author of four books, most recently Tying Streamers: Essential Flies and Techniques for the Top Patterns (Stackpole Books, 2020).

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