Bighorn Lifecyle Patterns – Mayflies

Bighorn Lifecyle Patterns – Mayflies

May 14, 2015 9:12 pm Published by 3 Comments


Sorting through fly patterns on the market today can be confusing as there are a plethora of ‘bin appeal’ patterns and not so many that promote ‘trout appeal.’ The patterns listed here are representative of the many styles of Mayflies we fish on the Bighorn River. Alterations in size and color will match most all tailwater Mayfly hatches you encounter across the Western US. Each stage of the mayfly lifecycle is covered, and in this post we focus on our most popular Bighorn mayfly, the Baetis (BWO).  We find these as all ‘must have’ patterns when visiting the Bighorn throughout the season.

Immature nymph


A staple guide pattern of the Bighorn River, this bug features an ultra skinny profile and just enough flash to fool the pickiest of fish. Keep this pattern sparse, which is the main trick to the effectiveness of this bug.

We also fish a glass bead version of this pattern. It is  extremely effective when fish get feeding heavy on the emerging Baetis nymphs.  Just add a gunmetal X Small bead.


Hook: 1XL nymph
Thread: Black 8/0
Tail: Natural Pheasant tail (3-4 fibers)
Body: Black thread
Rib: Ultra Wire – Gold – X small
Wingcase: Medium pearl tinsel
Thorax: Peacock herl

Variations: Psuedo Quill (cream body, cream thorax); Olive quill (olive body, peacock thorax)



Mature Nymph


This innovative nymph pattern is a highly important bug to have prior to most mayfly emergences. This imitates drifting nymphs just about to break the surface. The pronounced foam wing case acts as a ‘trigger’ to the fish, making them selectively pick out these types of bugs during the nymph drift. We fish this bug with a Tungsten bead as well, which doubles as an excellent dropper.

Hook: 1XL nymph
Thread: Dk Brown
Tail: Partridge (5-7 fibers)
Body: Nymph Dub – chocolate brown
Rib: Ultra Wire – Black – Small
Wingcase: Foam – yellow razor; 2 Dk. Brown Goose biots
Legs: Patridge

Variations: There is a BWO version of this pattern, but we have found the PMD version in size 20 fishes even better, as our Bighorn Baetis nymphs are almost black in color. If anything, you may want to change the foam wing color to a more olive tint to match the emerging BWO nymphs.


Emerging Nymph


Another Bighorn staple nymph pattern. Best representative of an emerging Baetis pattern, this bug can be fished deep or just under the surface. We have added a bit of flash to this bug, which we believe to have a bit more appeal to the fish. The wing of aftershaft gives this bug a lot of movement, similar to that of an ascending Baetis nymph.

Hook: 1XL nymph
Thread: Black
Tail: Partridge (5-7 fibers)
Body: Scud back – Black (cut thin and wrapped)
Wingcase: Grizzly hackle aftershaft
Flash: Black holographic tinsel – small
Dubbing: Grey superfine or rabbit


Variations: PMD (Rust body, Yellow antron over wings for split case – like appearance), Pseudo (lt. cream body and cream thorax with bleached aftershaft grizzly feather).

Stuck in the shuck Emerger/cripple


The key to this bug is tying it on a curved hook, allowing the back half to set down under the surface film, which is a component to the ‘stuck in the shuck’ appearance that trout find as easy prey. We find this bug to fish well in fast water as well as slower, flat water.  The combination of deer hair and cdc in the wing give this pattern awesome floatability and great contrast for visibility.

Hook: Light wire scud
Thread: Olive
Tail: light dun or cream z lon
Body: BWO dyed turkey biot (rib side down)
Wing: Dark coastal deer mixed with dark dun natural CDC
Dubbing: Olive fine and dry

Variations: PMD ( rusty z lon shuck, pale yellow body/dubbing and light colored dun CDC and light colored deer wing).



This guide-developed cripple features a slightly oversized wing, which aids greatly in visibility and buoyancy.   The weight of the wire on the body helps to ‘sink’ the rear half of the fly under the surface, providing an excellent cripple profile. Similar to the popular Smokejumper pattern, feel free to oversize the wing and bulk it up as the fish key more in on the slim body profile of this BWO Cripple.

Hook: Standard dry fly
Thread: Olive UTC 70
Tail: Partridge (5-7 fibers)
Body: Olive thread
Rib: Ultra Wire – copper – small
Wing: Dark dun natural CDC
Dubbing: Olive fine and dry

Variations: PMD (Cream body, light dun CDC wing)




Although not as important as the emerger stage, there are many times trout in the Bighorn will selectively feed on duns. This low profile Tailwater dun combines properties of natural CDC with the reflectiveness of Z Lon in the wing for an irresistible pattern. The key on this pattern is to keep a very sparse body. In fact, often times you can replace the dubbed abdomen with thread of the appropriate color.

Hook: Standard dry fly
Thread: Olive UTC 70
Tail: Lt. Dun Microfibbets or Coq De Leon
Body: Olive Fine and Dry dubbing
Wings/legs: Natural dun CDC , Med dun Z Lon (splayed out on both sides of CDC)
Dubbing: Olive fine and dry

Variations: PMD (Pale yellow body/light dun cdc wing)




We have always been a follower of Rene’ Harrop’s superb patterns and this is one of his best. I have slightly modified it to feature a higher-vis post for varying conditions. We also fish this with a black post for low light conditions. This pattern is our favorite in a Rusty Spinner version as well. The oversized hackle on the parachute is key in tying this bug and maintaining its profile.

Hook: Standard dry fly
Thread: Olive UTC 70
Tail: Coq De Leon – medium
Body: Olive turkey biot (rib side down)
Wing/post: Hi vis antron or para post
Dubbing: Olive fine and dry
Hackle: Oversized grizzly saddle

Categorised in: , ,

This post was written by Bighornangler


  • Curt says:

    Thanks. Once again, your shop is doing what no other fly shop is doing on the Bighorn. I find the information you provide the angler invaluable. Your detailed fishing reports, PowerPoints, articles, fly tying and fishing videos, online fly pattern books, and gear reviews provide a great service to your customers.

  • Dave Baxter says:

    Thanks for taking the time to help others learn, you’ve been crucial to developing my skills!

  • Jim says:

    Great information and great patterns. I’ve been fishing the Bighorn since they opened it – you have the most informative articles on flies and tying of anyone on the river. Your updates and fishing reports are also great. I live about 4 hours away and it helps take a lot of the guess work out when planning a visit.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.