Gomer the sounds you're talking about are just content sounds turkeys make while going about their everyday business. The water drop cluck is nothing more than a feeding/content cluck. Kind of like a feeding/content purr. You won't here hens make these sounds unless you're extremely close to them and they're absolutely at ease. They're the same as a excited cluck and purr just toned down.

I've used them and the little whip and whine on gobblers that are close and need that little reassurance to take those last few steps.