What masked or 'iconed' enemies can I still 1 hit headshot?

[Fokkas]

I have the original bow upgraded 2/2, the longbow, and the double bow - but before I start wasting arrows and giving away my position:

I've noticed many enemies I can 1 hit in the head with my longbow, and some of these enemies have some horn thing over them or have a mask or something (they stick out from the rest), but I don't know how to identify what "special" enemies I can kill in one hit opposed to some of those bastards that need 4 arrows to the head before I knock their mask off and kill them.

[Dakuwan]

Silhouette is how I can tell,

[Fokkas]

Originally posted by Dakuwan:

Silhouette is how I can tell,

How do you mean?

[Dakuwan]

the outside shape of the persons body once "spotted". you can tell if its the chieftan type enemies.

[Sparhawk122]

Shoot them in the back of the head where the mask is not covering with a bow.,

[Big Moustache]

Look for gaps in their torso armor: look where it shows skin. Throw a well aimed spear.
Edit: The heart is also weakspot.

[V]

For masked enemies that are not so easy to kill, a well-upgraded spear instantly kills when thrown. You can also use a close-up takedown if you have that skill upgraded.

[RoaringTreaty]

Those enemies with the shield icon are the hardest ones to kill from my experience. You can't get a headshot on them (never tried hitting them from behind with the bow/sling). The best I can do to damage them without getting near is to use a berserk bomb on them and let the other enemies slowly damage them for me. Otherwise I have to go in with my sabertooth tiger and smack them in the head about 30 times before they finally drop.