Great observation. A lot of anglers fish nymphs strictly on a dead drift, but swinging them at the end can be deadly, especially when trout are in a more aggressive mood. The key is knowing when to use it as a primary tactic versus just an accidental bonus at the end of your drift.

There are a few situations where swinging nymphs isn’t just effective—it’s often the best way to fish:

• Caddis hatches: Emerging caddis don’t drift helplessly like mayfly nymphs; they move—kicking and swimming to the surface. A slight swing at the end of your drift mimics this behavior and can trigger savage eats.
• Soft seams and tailouts: If you’re fishing a riffle that spills into a softer run, trout will often sit near the transition line, looking for food drifting naturally and food that’s moving across current lines.
• Cold water conditions: In winter, trout can be sluggish, but they’re still opportunistic. A gently swinging fly mimics a slow-moving prey item, which can be easier for them to eat than something drifting quickly past.
• Steelhead and aggressive trout: If you’re fishing for steelhead or big brown trout, a nymph on the swing can act more like a mini-streamer, provoking reaction strikes.

So how do you do it right? It’s simple. Let your drift run its course, but instead of immediately picking up your line, lower your rod tip and let your flies swing across the current naturally. A slight lift or twitch can add even more movement. If you start getting more strikes on the swing than the dead drift, you’ve got your answer—adjust your approach accordingly.

Try playing with this technique next time you’re on the water. You might be surprised at how many fish prefer a nymph that’s moving rather than one that’s just drifting!