Trout Food: Mothers Day Caddis

Mother's Day caddis is one of our most coveted early season hatches. With the right conditions, some of our best dry fly fishing of the season will happen during this hatch. When planning to catch this hatch it’s important to look for consistent weather and water temperatures. As a general rule, we find that three days of consistently warm air temperature in mid-May will get this hatch underway. Beyond timing, understanding Mother’s Day caddis life history is also key in making sure you maximize your time when you do hit the hatch. If you hit this hatch on the right day and fish it the right way, you could experience some of the best fishing of your life. So, here’s what (we think) you need to know about fishing the Mother’s Day caddis hatch.

Aaron hooks a nice Bow River brown on a Mother's Day caddis. 


Classification (for the nerds):

   What we know as Mother’s Day caddis is a member of the family Brachycentridae, which includes what many know of colloquially as the ‘grannoms.’ Species from the Brachycentridae genus form many of our early season caddis hatches from May through June. The larvae of the caddis in this genus are cased, which is important to note for fishing larva ahead of the hatch. Brachycentrus occidentalis is known to be the specific species that we refer to as Mother’s Day caddis in Western North America.


Bow River Mothers Day Caddis

Mother's Day Caddis on the Bow River 


Where to find them:

   Mother’s Day caddis hatches occur on many of our trout streams, particularly those that are lower in elevation. The Bow River and Crowsnest River are probably the best places to search for this hatch as they can be in good shape at this time of year and are open to fishing in certain sections. Although many streams likely have Mother’s Day caddis hatches, most streams in ES1 are closed to fishing while this hatch is occurring. Be sure to check the fishing regulations to ensure that where you’re fishing is open.


Larval stage:

   As with most caddis, B. occidentalis have a life cycle that takes approximately one year to complete, meaning their hatches occur at nearly the same time year after year. Nearly all of this time is spent in the nymphal stage, where very small nymphs mature through multiple instars towards maturity. Mother’s Day caddis larva are cased caddis that use whatever they can find around them to form ‘cases’ used to protect themselves from predators. Larvae do leave their cases to feed as they filter vegetative material from the water around them. Larvae are available to trout all year and will be readily eaten both in and out of their cases. I haven’t heard of many cases where specific cased caddis fly patterns have been particularly successful on the Bow, but small pheasant tail patterns and other general nymphs could certainly be taken by trout as cased caddis imitations. Caddis larvae are certainly a part of a trout’s diet throughout the year, but as with most nymphs, they become most important to fish and anglers prior to and during the emergence or hatch, because this is when fish see them most.



Pupal stage:

   As a caddis nymph reaches maturity, it will pupate within its case in preparation of emergence.  Pupation is the first step in transitioning from nymph to adult and probably the time during which trout eat caddis the most heavily. Once the conditions are right (a few warm days in May) caddis pupae emerge in massive numbers from their cases, providing excellent and consistent food for trout (ideal for anglers.) B. occidentalis pupa swim to the surface and emerge into adults on the water. Pupae can swim to the surface quite quickly, so a swung fly or Leisenring Lift can be very effective. Gary LaFontaine’s famous sparkle pupa in caddis green is very effective here although I tend to fish a green soft hackle with equal success during these hatches. Early in the hatch these patterns can simply be dead drifted mid water column as it is likely some pupae will be dead drifting prior to emergence. Mother’s Day caddis pupae are usually #14, but go up or down a size depending on the size of naturals. I have found that tying a hot spot on your pupa can help your fly stand out amongst naturals during heavy hatches.



Adult Stage:

   Once pupae reach the surface, they quickly emerge into adults, which have the typical ‘tent wing’ shape of all adult caddis. Newly emerged Mother’s Day caddis adults retain the light green coloration of the pupa, but will become darker in the hours and days after emerging. Newly emerged adults will skitter and attempt to fly across the waters surface until they take off or end up on the river’s bank, where they will subsequently take cover amongst vegetation and mate. After mating, which usually occurs in the days following emergence, female B. occidentalis return to the river for oviposition. Mother’s Day caddis is known to oviposit while drifting or skittering on the water’s surface, where they are once again available to trout. Fish will feed on the lively females that are ovipositing as well as spent ones on and below the surface.

   Make sure to be observant at this point in the hatch, because their will likely be caddis in a variety of life stages in and on the water at the same time, but the fish may be focusing on only one of those life stages at a time. I have written another, more in depth, blog about fishing caddis hatches here. If you can, watch individual fish to see which caddis they are feeding on and select your fly pattern from there. The two main patterns I keep in my box for dry fly fishing during Mother’s Day caddis hatches are an elk hair caddis and a low riding CDC caddis. If I see that fish are selectively feeding on skittering caddis I will fish the elk hair caddis, if I can’t visibly see the caddis they are feeding on, I will likely fish a very low riding, delicate CDC pattern. Although many other fishing scenarios certainly exist during this hatch.


Mother's Day Caddis patterns


Tying a simple caddis pupa for swinging and dead drifting:



If you have further questions about fishing Mother’s Day Caddis, come by the shop and ask us some questions!

By Mark