Well, if nothing else, I seem to have gotten people talking again... in some ways it's gratifying to know that I'm not the only one having difficulties with this bird. She was swimming in the channel that runs along the east side of the drained cell (3?), south from the north entrance. It was one of the ducklings that first caught my eye, as I was checking out the Yellow Warbler on the far side of the channel. I may try to sneak in for a couple minutes this morning, but I'm on my way to Ottawa with an impatient passenger.
If it helps, I've cropped and resized the picture on Flickr...

I have other pictures as well, but the light was harsh, and she knew I was there, and was trying to keep her babies safe from me... I actually had to run down the opposite side of the berm, out of sight, to get this shot, and didn't want to distress her too much by trying to get closer.