With Bozeman’s central location between the Yellowstone and Madison Rivers, it is a great place to base your stay if you want to fish the famed Mother’s Day Caddis hatch. This hatch is very specific to the water temperatures on the Madison and Yellowstone Rivers. Water temps must be around 52 degrees to key the brachycentrus occidentalis to hatch in the millions on these two trophy waters.
This hatch starts as the May weather begins to warm up and coincides with early season snow melt, making it a fine dance between finding fishable water and fishing this heavy caddis hatch. The Yellowstone River is a little more unpredictable than the Madison River as the Madison is controlled by a few dams prolonging runoff for a longer period of time. The Yellowstone has many more tributaries that may rise and stain the river on short notice. We generally concentrate fly fishing from the town of Livingston upstream, as this is where the heaviest hatches are and generally less snow melt entering the river system.
The Mother’s day caddis hatch on the Madison River starts on the Lower River and then makes its way upstream, much like the Salmon Fly hatch. You may be able to fish this hatch for up to a week following it upstream if conditions are favorable.
The best dry fly fishing for this hatch occurs on either overcast days or fishing later in the day. As the hatch gets going, many of the trout are keyed into both the nymphal and emerger stages of this hatch. Fishing a double nymph rig or dry dropper outfit works best. As the sun drops behind the mountains or in the shadows, you will find more and more fish feeding on the surface. Some of the best dry fly fishing will be near the end of the day, when the sun isn’t beating down on the fish.
We generally fish dries a size or two larger when hunting rising trout on the Yellowstone or Madison Rivers. It can be hard to see your dry fly in the mix of many other “naturals,” and by fishing a larger pattern, not only for you but for the trout as well, you may see a better, bigger meal.
Swinging a soft hackle fly can be very productive just under the surface to imitate the emerging Caddis fly.
Peacock herl and olive colored patterns seem to be the most productive patterns to use for this hatch, both on your nymphs and dry flies.