Kind of a stretch for the Soft~Hackle Journal to offer a fly meant to simulate a mammal, I admit. Take my word for it I am suitably shame-faced while writing this. But I did see that film where the Mongolian guide skinned a lemming, stuffed the skin with foam packing peanuts, & sewed the whole thing onto a hook to create a damn realistic (& great-floating) lemming fly, then used it to catch a giant taimen. Six foot long trout. Inspiring stuff. And besides that, the little mouse fly is just too cute.
But there’s nothing cute about trout large enough to want to eat a mouse, or the way they’ll eat it, & that’s probably the real reason I flaunt the mouse pattern here. I suspect the idea of fishing a mouse as bait appeals to my dark side – the side that lurks on the bank at night, casting blind, lasciviously skating a giant fly, anticipating a savage bulge that will trouble the water & rise like an infuriated Creature from the Black Lagoon suddenly busting from the inky stream to crush the hapless mousy meat. Nothin wrong with a little excitement in the dark. Sport.
Funny thing is: that kind of nocturnal behavior often occurs on water so technical, in daylight, there is only the wisp of a chance that same fish will even sniff your #22 Trico or BWO fished on a 20-foot leader.
We generally associate hair-mouse lures with bassing or night fishing for brown trout, though big rainbows like them too (results on a secret spring creek do attest). Bull trout love them. And I suspect the imitation might work well anywhere there are sizeable trout & active mice present, regardless what species the trout. Certainly a good pattern to have in the kit. Well worth a few casts over a favorite spring creek after an evening hatch has dwindled into darkness. You never know.
Staying versatile (The Dude abides), I’m committed to fishing the mouse next season more often than I have in the past, so’ve been playing with deer hair designs looking for a quick one. At night (when the imitation is best fished) you probably don’t need anything more than a wad of hair, & some tie just a ball of clipped deer hair for the body, but I wanted something that would fairly satisfy my aesthetic opinion on a swimming mouse profile, while easy to tie without a lot of hair packing & trimming.
Hook: #4 light wire hook
Tail: a single saddle hackle – gray, light ginger or white are good
Body: deer hair – tie in about mid-shank, arranging a thick collar around the hook shank, hair tips extending slightly beyond the hook bend – tie in more deer hair, then pack & trim to mousy head shape.
Ears: probably not necessary but, to satisfy my own sense of aesthetics, I added 2, made from orange art foam (I was out of pink)