The warm and sunny months of June through August are periods of heavy damsel activity on most still waters in the region. There is a heavy hatch that occurs in June that gets the most attention, but this nymph is widely held to be one of the top 5 or 6 food sources for trout from May through September. I've found that even when trout are keyed in on other hatches, they won't often pass up a well presented damsel. If you can sight fish for trout and get this pattern out ahead of your quarry w/o spooking it on a 4x leader, there's a good chance you'll only need this one fly during most of the daylight hours.
Things to consider when imitating a damsel fly:
- Are you seeing them hatch? Seeing them fly about as adults is one thing, but they live a long time, so you'll want to watch for them crawling up bull rush or swimming up towards the surface. Fishing during a heavy hatch (i.e. late June) can be tough, the fish see tons of these nymphs and have likely already gorged themselves, so fooling them is tough. Secondary hatches in July and August end up netting more fish. Also, these things hatch mid day, toss streamers in low light morning/evening situations and save the damsels for mid-day.
- Find where they're likely to migrate, find shallow weedy areas and reedy banks that allow the nymphs to crawl out of the water to hatch. Damsel activity is high in these areas and your quarry will often times cruise these weed beds looking for them.
- Understand how they swim. These nymphs are pretty decent little swimmers, making lateral movements of a few inches or so at a time, then they rest, then they move, then they rest. You don't need or want a fast or constant retrieve, 3 inches, then stop for 4 seconds, then 3 more inches, etc. The movement is useful in getting the fish to see the nymph but they often take it on the rest when the fly is still.
- Match the hatch. Many damsels are light tan or olive green, and a #12 or #14 fly on a floating line is just about perfect. Having a pronounced head w/ eyes is a plus and something to imitate their 3-pronged tail is a must. There are dozens of patterns out there and some look more the like real thing than this pattern. What I like about this pattern is the fact that its only slightly negative buoyancy. Weighted flies will start to sink on the rest, this fly won't sink much at all which makes it look like a real damsel.
- If you get a refusal, make a fast strip to get its attention again, then use trial and error to see if more movement or rest will invoke the take.
This is geared towards sight fishing skinny waters, deep water techniques can vary (and intermediate line may be required), but if you can see you're quarry, you can get 50-75% of them to take it. Just get it out 12-15 feet (minimum) ahead of them, let them discover it naturally and not be "alerted" to it by a splash. Good Luck!