With the popularity of the two handed rods and spey casting, intruder style flies are becoming more and more popular. The Intruder style of tying offers the fly tyer lots of room for interpretation. The flies are usually sparse along the shank with long flowing hackles used to give the pattern volume. Intruders are tied to represent shrimp, and prawns, so using materials with long flowing hackle helps to trigger the feeding instincts of Steelhead returning from the salt. Some materials that are commonly used in the construction of the Intruder are Rhea, Guinea Fowl, Ostrich, Lady Amherst tail, Polar Bear, polar chenille, marabou, schlappen, dyed white peacock and Blue Eared Pheasant.
Phil Rowley has put together a nice tutorial based on a pattern from BC’s Scott Baker-McGarva. Phil offers an informative look at the construction and history of the Intruders. He also dives into some deeper detail on some of the materials used for tying these spey flies.