Spring Bugs

Sean Visintainer - 04/28/17


The variety of spring

"What are they bitin' on?" I think we all know what movie that line is from. It is also the the most common question in the fly shop. And rightfully so. Anglers love knowledge, the more we have, the better our odds. Spring is an interesting time of the year because we have so many different bug hatches happening on any given day. From micro midges up to massive stoneflies and everything in between. So what are hatches you can expect during the spring on the St. Joe, NF Coeur d'Alene, and Clark Fork Rivers? Here are the key players...


Mainly an early spring deal, although they will hatch consistently through runoff. Downside is as the other bigger insects hatch the fish forget about these little guys rather quick. Upside... who they hell wants to fish a size 20 when they are feeding on a size 10!

  • A cluster of midges clings to a rock.
  • Mating midges on the Clark Fork.

BWO's (Blue Winged Olives)

Spring and fall bring reliable blue winged olive hatches across the west. This bug should be a staple in every fly anglers box as they will hatch more often than any mayfly. Size 16/18 is the norm. A rainy day favorite for many anglers. Yes they do hatch in the sun too, that's a big misnomer of this particular bug.

  • A bwo on the North Fork Coeur d'Alene river.
  • A group of bwo's on the Clark Fork River.
  • A solo blue winged olive on the Clark Fork River.

Nemoura Stones

The smaller cousin of the skwalla stone. This little fella is about a 12/14 size on average and typically hatches right before the bigger skwallas do. Often times this hatch is mistaken for the bigger skwalla. A small black chernobyl typically works great when imitating these guys.

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March Browns

These should be renamed April Browns. I can't recall many days on the water that these size 14/16 mayflies hatched in March. Can you? In our area they always seem to be early to Mid April hatches. Nonetheless, it's a spring staple that typically bridges the gap between the small midges and blue wings to the larger skwalla stones and gray drakes.

  • A March Brown mayfly clings to a Winston Boron IIIx rod on the Clark Fork River.
  • Guide Britten Jay captures a March Brown on his Yeti Soft Cooler on a day off, Clark Fork River.
    Photo by Britten Jay

Skwalla Stones

Ahhhh yes, a favorite of anglers and trout. An inch long meal of protein. Easy to see and fun to fish. Who doesn't like slapping a large stonefly down on the water and watching fish just get stupid for it?! Skwallas on the NF CDA, St. Joe, and Clark Fork will hatch as early as late March and will continue into May. Cool thing about that time frame is the fish know that bug should be there so it's always a safe bet to prospect with.

  • A skwalla stone crawls on angler Mark Poirier's hand early season on the Spokane River.
    Photo by Sean Visintainer

Gray Drakes

The sailboat of the river bugs. Large and in-charge. This chunky mayfly dwarfs the March Browns and BWO's, there is no mistaking the flotilla of these guys when they are out. I think drakes must taste like candy to trout because if there are other bugs hatching at the same time you can forget about those patterns and focus on the drakes.

  • The fly soldier Gray Drake rests on a Winston Boron Plus Rod.
  • The large Gray Drake climbs it's way through moss on a rock, Clark Fork River, MT.
  • Profile of a Gray Drake on the Clark Fork River.


In our area salmon flies can hatch as early as mid April. That's easily 1-2 months sooner than other places around the west. Why? Not sure. Maybe lower elevation? Maybe warmer water? Who knows and who cares. I love salmonfly fishing. I would take a month off if I could and chase this bug around the west. Look for these creepy crawlies starting now on the NF Coeur d'Alene and St. Joe. We already have confirmed reports of a few.

  • Jennifer Nepean holds a salmonfly nymph.
  • A large salmonfly crawls up Sean Visintainer's arm.
  • The orange of salmonfly stone is hard to mistake.