That's right bucks growl to call in estus doe's. I heard of the clicking sound too. The makers of the buck growl sell it with a dvd that show's you how to use the growl and clicking sounds to call in bucks. I think if you visit thier website you can view the dvd for free. I heard a old buck use a deep tone grunt growl once,and call doe's in making that sound with my grunt call. Primos sells a roar which is about the same,but adds a snort wheeze to the call. Both seem to work from what I've seen.
"Let a young buck go, so he can grow."