I'm new to bow-hunting but not to hunting. This year I have been stalking foxes, kangaroos, wallabies and one or two feral cats in local bush (not to shoot all of them, that is illegal here) for practice and recreation. Without fail, they sensed final movement of the bow and I felt sure the bow stick coming up, stained black, was part of that - so I broke it up with grey streaks and it works much better. I can lift it to aim at twenty metres and they watch but don't jump.
I know from experience too that simple grey-streaked camo works much better at dawn/dusk than black, so I would reckon you could just dull down and break up the outline of your bows. Charcoal would do that as suggested or you can leave wire-wool in vinegar for a good dye.