You must be prepared to do this type of research. I was not on the first night. On the second day of my overnight expediton I was more prepared. The first night I heard tree breaks and movement. My vidoe camera ran out of juice and I had to just use a still camera. I did miss out on some activity.
The second night, I got down to the waters edge and left a continuous camera for about twenty minutes. I did not want the camera that far out in the jungle after it got total dark. I may not have been able to find it. So I returned, and studied the results. I heard, at least twice, a howl or bark. At the end you can hear one good, clean knock.
The area was more active the night before, but at least I got something.