Spruce Moths: The Quiet Hatch

Friday Aug. 1st, 2014

People travel to our great state to chase the famed Salmon fly hatch, the prolific Mother’s Day caddis hatch, our blanket PMD hatches, and our epic hopper “hatches” (albeit not in recent years). You don’t hear about many people coming to Montana with the intention of targeting the annual Spruce moth hatch. Heck, I didn’t even know what a Spruce moth was until about 6 years ago.

The problematic spruce moth may be one of the most under appreciated hatches in our area. I say problematic because the larva stage of these bugs feed on fresh foliage from Fir and Spruce trees in the area and can stress trees out to the point of death. While I acknowledge that they are an issue for our forests and we’d be better off without them, they are also a great hatch to fish, and if they’re here why not fish them? Here are a few reasons why the Spruce moth hatch is worth a few of your days on the river this summer.

First of all, fish are fat this time of the year. Trout have been feeding all summer and are not the starved, snake like fish that you catch with the first hatches of the year. They’ve had time to feed on Caddis hatches, PMD’s, Salmon Flies, all sorts of stone flies and bunch of bugs in between. Fish are simply bigger in the summer than they are in the spring, and if you don’t think size matters just ask any fisherwoman.  

Spruce moths are a large, high calorie meal. While fish may have had all spring and early summer to eat, they’re extremely opportunistic and are always looking to get bigger and stronger. Spruce moths offer up a big tasty meal that trout just can’t seem to pass up. Trout don’t miss the hatch, and neither should you.


This is by no means a technical hatch. These are large bugs and when they hit the water they don’t stay still, they’re trying to get off the water by pumping their wings and consequently making a ruckus. As you can imagine this drives trout crazy often eliciting acrobatic strikes and shark like eats; it also means you don’t have to worry about your presentation. Often times a perfectly dead drifted fly doesn’t entice fish as much as a moth pattern that is skated or twitched across the surface.  

6x tippet need not apply! Most Spruce moth patterns come in hook size 12 and 14, not 20 and 22. 3x tippet is fine on these patterns and will allow you to land more fish and lose less flies. With the only other viable hatch of August being Trico’s which require size 20 and 22 hooks and 6-7x tippet, the Spruce moth offers old eyes an easier alternative.

Waders are not necessary. Gone are the days of standing in 40 degree water with a snow storm covering the banks while Blue Wing Olives blanket the water. Spruce Moths show themselves during the hottest month of the year when the river is a welcome solace from the mid-summer heat. Grab your wading boots, some shorts, and revel in the cool water while fish dance across the water chasing these fluttering moths.  

Spruce moths are more widespread than most realize. Most think of the Gallatin when they hear about the Spruce moth hatch, and while the Gallatin does have an amazing Spruce moth hatch every summer, you can find Spruce Moths on the Boulder, Gallatin, Madison, Big Hole, and many different creeks in the area. Basically if the piece of water you’re fishing has Spruce or Fir trees along its banks, you can count on Spruce moths hatching in early August!


The hatch generally gets started at 9 am and will run until the heat of the day really kicks in. The hatch will pick back up in the evening for another round of frenzied feeding. It is not uncommon for fish to stop feeding in the middle of a heavy Spruce moth hatch. The moths provide such a large food source trout tend to gorge themselves on the moths and will wait until they can make some room to continue feeding.   


Our favorite patterns for the Spruce moth hatch are D’s Sprucie in a size 12, Dan Delekta’s Tan Twisted Baby 12-14, and the Parachute Spruce Moth size 14. The ol’ Elk Hair Caddis and Snowshoe Caddis in tan work great as well!

While August may not be the most prolific month for bug hatches, the Spruce moth hatch is the summer’s under appreciated exception. Don’t let the trout be the only one to take advantage of this great hatch!