I went to look for Mergansers and came back with

... ice-patterns from the southern edge of the reservoir.  Most of the water was covered in a thin layer of ice, so there wasn't much swimming going on.  All the birds seemed to be resting at the western end though there were a few enjoying the pools of water at that end.  

I was disappointed not to see the Mergansers as I'd taken my longest lens, but had not expected to find such amazing ice patterns - the lens was exactly right for that activity.

I see another explosion book project coming on.

And my greatest surprise when looking at the thumbnails was that there were three female Mergansers among the ducks - too far away to get a decent shot but I'm sure a proper bird photographer with one of those enormous lenses would have managed it.