Random question I thought I would ask here - I am a birdwatcher in Atlanta, GA and went out to a nearby park this morning around 7:30am. It was in the 30s with a good frost covering most everything. Anyway, I was standing still and then I heard what I thought was a mallard duck. I looked overhead and saw nothing, then realized it was coming from the forest floor. It was a repeated 4 notes very similar to a mallard. It was repetitive though like an insect or frog might be. 4 duck like quacks and then a moment of silence before it would repeat. I could not pin point the sound... it seemed to move with me somehow. I would turn one way and then it would seem like it was coming from behind. Very strange. Some kind of frog? Insect? It's December so I would think frogs wouldn't be calling.