Start thread in the body colour (yellow here) on a #12 standard dry-fly hook and take it back close to the bend.
Stack about a dozen moose mane fibres and bind them in as a tail at least one body-length long. Cord the thread clockwise so the first wrap bites, then take a couple of medium wraps working back.
Leave the moose butts in place and bind forward over them with loose wraps to thicken the underbody, stopping short of the front. Tighten with a few firm wraps, pull the butts up and snip them close, then bury the stubs and return the thread to just in front of the tail.
Stack a medium tuft of natural deer hair with the underfur removed and bind it in with the TIPS POINTING FORWARD over the eye. Where you catch it in sets the body length, so take a couple of wraps back before binding forward with loose-to-medium wraps. Snip the tips that crowd the eye.
Build the body with a couple of layers of thread over the deer hair (tie in floss and take two layers instead if the body is too thin), stopping a little short of the eye to leave room up front.
Gather all the deer hair butts, taking care not to grab the moose tail, and fold them forward over the top to form the hump. Pull tight for a flat hump or less tight for a rounder one. Cord the thread, lock with two tight wraps, then add several more, with a wrap or two down into the hair.
Snip the excess deer hair off close in front, bury the stubs, and leave the thread at the back of the head area.
Bind in a medium tuft of white calf tail trude style, unstacked, lying flat over the back with the tips reaching the rear bend. Pinch-wrap three turns, check it sits, then add two more. Snip the butts close at an angle and build a small thread ramp so the hackle has a smooth base.
Tie in a grizzly hackle with barbs about one and a half hook gaps or a touch shorter. Tilt the fly nose-up so the wraps do not slide, and take four tight touching turns for a heavy hackle. Catch it off without crowding the eye.
Sweep everything back and take a few wraps to make room, whip finish before the barbs spring forward, then snip the leftover feather and any fibres crossing the eye. Add the smallest drop of head cement.