I often share my waterfowl images over in the "birds" section of the forum, but thought I'd post these here so that those of you who don't often get over to "birds" could enjoy them.
These were shot during the spring breakup of ice on the Methow River, about two months ago right here in my home county. They were taken from an improvised blind that I spent the better part of a week and a half in. The blind was set right on the ice, so I was able to get a fairly low angle for most shots.
I used the 5D for these, and had the 2x converter on my 400 2.8. I've found that the 2x tc does work well if there is a lot of light. The relative success I've had with the 2x saves me the need of getting a 600mm or an 800mm lens right now, which I simply can't afford, anyway.