Ok odd,was talking to a bud,he said that sometimes in gangs,when doing a hit,a place could get "tagged",(spray painted)but if it is a bird,or bat looking symbol see if it could be a bird with no head or tail.So I'm like ok,why..then he says,evil **** ,just some crud ya don't wanna mess with.He asked me why I asked,I kinda blew off his question,gotta pick your info to the who, very carefully in my field,ya know.So I ask him if he could direct me to some books or something more on this,he says "hell no,just leave it alone! I'm telling you it's dark f- ****!!!We bs'd about some other cases and then hung up.thought that was odd.