SnowWolf said:
looks like... *_markings is used for location and color, while *_(marking) is used to describe the marking. _Marking seems to be used erratically.

*_marking seems to be mostly used for shapes, but those should probably be moved into the other two groups for consistency.

Anything in brackets tends to be a disambiguation.
*_(marking) consists mainly of things with other meanings: mask_(object) <> mask_(marking), mole_(animal) <> mole_(marking), socks_(clothing) <> socks_(marking), and so on.

Cheek_circle_(marking)? Cheek_spot_(marking)? blush_(marking)?

I was going to suggest cheek_patch_*, since that's what it's called on birds, but after a Google image search it doesn't seem like a good idea.