What it is
UV2 Mallard Flank is mallard duck flank feather that’s been put through Hareline’s UV2 double-dye process. The feather is naturally webby with a barred pattern, and it adds UV fluorescence and UV reflectance when it’s on the hook.
What to tie with it
Use it anywhere you want soft, mobile feather fibers: dry and wet fly wings, streamer wings, and big soft hackles. It also works great pulled as individual fibers for emerger legs, nymph tails, and nymph legs, or trimmed and shaped for cut wingpads. On crustacean patterns, the webby flank makes convincing claws and shellback-style coverings for crayfish, crabs, and shrimp, and it’s right at home in looped-wing emergers, Spey flies, and classic salmon flies.
Flies and the fish they're for
On Light Cahill and Dark Cahill Dry Flies, mallard flank shows up as a wing material for mayfly hatches, the kind of dry you’d fish for trout on rivers and spring creeks. The Light Cahill Wet Fly and Dark Cahill Wet Fly use it for wings on a swung or down-and-across presentation for trout in riffles and runs. In a Zug Bug Nymph, it’s part of the buggy profile that gets eaten by trout in freestone rivers and tailwaters. On a Zoo Cougar Streamer, mallard flank can be used in the wing for a larger baitfish silhouette, a streamer you’d throw for trout and also for warmwater fish like smallmouth in rivers.
How it compares
Compared to standard Hareline Mallard Flank Feathers, the difference here is the UV2 double-dye process that adds UV fluorescence and reflectance. If you’re thinking about wood duck flank as an alternative, the barring is similar, but wood duck is typically the higher-cost option.
