There is no method to spawn Quillmane aside from killing any and all wandering mobs (Brother Qwinn excluded).
Slaughter all roamers: Wolves, Centaurs, Elephants, Gnolls, Lions, Aviaks. You have a chance to get a rare mob. Escaped Splitpaw Gnolls are the most common, guessing around 40% chance. Quillmane is closer to a 1 or 2% chance. All other named are in between these two.
So yes, just kill regular mobs, keep checking tracking and depending on how fast you can kill, you will see Quillmane.
这也算是最笨的刷新方法了