Great video. The one in the pond is for sure a female, and the one in back on the edge of the pond is one as well. The one on the edge that's closer to the camera doesn't seem to have grown into its adult voice yet, so I can't tell with that one. If you have heard that one quack loudly, then it...
The ones that belt out loud, quack like noises are females. Males have a quieter chatter. Some say it sounds raspy but to me it's just an odd kind of mechanical sound.
I think you have to link videos from somewhere else, which means you have to post them at somewhere like Youtube first. I could...