As winter begins to fade into spring I begin to dream of those warm, sunny days of late April and early May; just before the spring sun becomes strong enough to send the first rush of melting snow coursing downstream that marks the beginning of the annual runoff. Those days hold numerous fond memories that have been forged over many years during the halcyon days before the high cold water turns the local waterways into floodways filled with flotsam swept off the sandbars and scoured from the banks.
In many areas of the western United States the first notable hatch of the season is comprised of caddis flies. Commonly referred to as "The Mother's Day" caddis hatch these prolific insects can begin hatching as early as mid-April or as late as the last week of May. The key to the most productive fishing is the timing of the hatch; if it comes after the annual spring run-off has started angling opportunities fall off sharply. However, if you hit it correctly the results can be nothing short of fantastic.
Common called the Grannom, scientifically they are in the genus Brachycentrus for the more technically minded among us. You can find some members of this species in trout streams across North America, and in the western states they can hatch in prodigious numbers that can boggle the mind.
I recall one day in late April on my home river, the Yellowstone River just south of Livingston, Montana. The weather had been a typical spring mixture of a few warm days followed by a snap your head back cold front. During the warm days I had found a few caddis hatching but there were not enough insects to bring create much interest on the part of the trout. Then, after a cold spell that brought snow and temperatures down in the teens, a strong high pressure settled in over the area and for a couple days a warm Chinook wind swept down the east slopes of the Rockies and the temperature shot up into the mid-60's during the day and upper 30's during the nighttime hours. Even though it was mid-week told my clerk that I would not be back after lunch, and I rushed home and jumped in the old fishing car and struck out for the Yellowstone. When I arrived at the river a few miles south of my house a few caddis were beginning to hatch, I quickly assembled my fly rod, grabbed my vest and set out to do battle.
The Chinook wind had died away, the late spring sun was strong, and over the next couple hours the caddis came, and they came and they came. I was using an old favorite, an Al Troth Elk Hair Caddis trailing a Hare's Ear soft hackle. Early in the hatch the Hare's Ear produced the most fish but as the hatch intensified the more and more fish switched over to the Elk Hair. In my memory the afternoon is a blur of activity. It seemed that every trout in the river was on the feed, and nearly every cast brought a strike. There was a mix of browns, rainbows and cutthroats along with a generous helping of Rocky Mountain Whitefish. What amazed me most was that I had the river all to myself. Most of the fish were twelve to fourteen inches long, but I managed to land a couple nice browns that pushed 18 inches on the tape. They were stuffed with caddis and were still feeding.
As the sun began to drop in the late afternoon a cool upstream wind began to blow, and the hatch slowed and then stopped as quickly as it had begun. I glanced at my watch and realized that three hours had passed since I arrived at the river. I sat on the bank and watched the river flow along, its surface unbroken by a single rising fish or hatching caddis. The rocks along the bank were covered with a crawling mass of mating and egg-laying caddis. Robins, song sparrows, red-winged blackbirds and several other species of small birds were hopping around on the rocks taking full advantage of the bountiful feast.
The following day there were caddis flies flying around in downtown Livingston but the warm Chinook winds and the spring time sun had worked their magic on the winter snow pack. The Yellowstone was the color of old coffee mixed with a dash of cream and the Mother's Day caddis fly hatch became a memory for another year.