White perch rarely, if ever, surface feed like many panfish species. Coming from brackish and salt water roots plays a part in that. Adults are very much piscivorous but also eat aquatic insects. I've seen unreal midge and mayfly hatches that had the water absolutely boiling with bluegills, bass, crappie, shiners, and bullheads and yet never a single white perch. I was therefor never surprised to find no mention of white perch on dry flies in any of my reading. In fact, some books and articles that I have read have specifically stated my first sentence. Last year's spring run had my trying small foam panfish flies for them, and though I got boils and bumps I never hooked one or even came close, they never actually opened their mouths. I figured these fish were aggressive enough that the floating flies got their attention, but they lacked the instinct to actually eat them like a bluegill or trout would. But the mere fact that they had shown interest in the dry made me think a little.
A year has passed and I saw plenty more evidence to suggest white perch just wouldn't take a dry fly. And now the spring run has commenced and today I found perch in massive numbers in shallow water. All I could think was "These fish aren't supposed to eat dry flies? Challenge accepted!".
Now I'll say this, it took some doing. I had to get the twitch-pause cadence down to the perfect speed and my hooksets had to be just perfect. But I was getting white perch on a dry fly, a Puterbaugh Caddis. Actually floating. It was crazy. In the pile of white perch was a little yellow, though that was less surprising as I have caught them on the surface a few times before.
Challenge accepted, challenge completed.