The Big Bertha Soft Hackle is a spider style fly, weighted or unweighted, tied on a large hook and using pheasant tail for the body and Partridge for the hackle.
This pattern uses a died-red pheasant tail for the red butt and, in the example in the photo, a 3.3mm tungsten bead on a size 8 hook.
The body is pheasant tail and the hackle is one of the largest feathers from a partridge skin – near the tail.
Again, I use this for Chub, but larger fish of any river species find it delicious.