A small game hunting license and a sporting ethic are all that are needed. Well, maybe cunning and patience help, too. Crows are wary. If a person walking in the forest suddenly stops, any crows nearby will instantly fly away. Some studies suggest that crows can count and that if three men enter a forest but only two leave, the crows won't return to the area.
Crows also have good eyesight.
Masks, gloves, everything. But despite their wariness, crows can be fooled. They will flock to calls from a hunter. The distress call is one of the best ways to attract them. Mimicking the call of a great horned owl or red tailed hawk will also bring them in.