The soft hackle emerger is commonly called the Partridge and Green, Partridge and Orange, or Partridge and whatever you choose for the body. I like to tie these sometimes with a bead and sometimes without a bead. I generally tie these in sizes 14 - 18 to imitate caddis or mayfly emerging from the bottom. I'll fish these behind a strong floating dry fly, often attached by 18 inches of 5x tippet, and you really just dead drift your dry, let it swing at the end, and can even hold your tight line there until you feel a take. It's an extremely effective pattern and very easy to fish. In the old days in Europe, they fished this fly with just thread and some partridge feather wrapped around the front of the fly.
It's a pretty easy tie. Start with the thread color of your choice by the hook eye. Tie in a piece of wire (copper, gold, silver, etc) and wrap over it to the hook bend. Advance your thread back forward to about a hook eye length behind the hook eye. Take your wire and spiral wrap it to your thread then tie it off and cut it. Strip back one partridge chest feather from the base of the quill up until you take off all of the fluffy part of the weather. Tie in the tip of your feather and take two wraps around your hook going towards the hook eye. Hold the feathers towards the back of the fly, tie them in securely, build a small head, whip finish, and add a touch of head cement.
Hook: Size 14 through 18 dry fly hook
Thread: Your choice of color
Wire: Typically copper, silver, gold or a bright green
Feather: Whiting Brahma Hen Hackle or your personal partridge chest feathers