One of the more commonly reported sounds is wood knocking. Now whether wood knocking also includes vocalizations, hand slapping or rock clacking is open to debate.
Another type of knocking or banging heard in the woods is what sounds to be banging as if on metal.
From the book Gorilla Behavior by Terry L Maple and Michael P Hoff (Van Nostrand Rheinhold Co., New York: 1982 ) we read on page 197,
“In captivity, as we have seen gorillas incorporate the built environment into their aggressive displays. They will drum, pound, and kick against any surface that reverberates the sound. Their use of the environment to create noise may be seen as a kind of tool use, and in gorillas the behavior is clearly an extension of their natural chest-beating display.”
Chest-beating has also been reported from this location. Using a remote recorder I recorded the following sounds on the night of the 30th of March 2011.
Click here to listen to sound clip: Metal Banging 2
Each one of the ten bangs is very short and at a distance, therefore the signature on the photo above is small. There is old farm equipment close by so perhaps something was banging on it.