Tiny Little Unknown Duck?

Out filling in forms today but not so bad as the weather was lovely and the scenery was spectacular down beyond Ardfern. Beautiful part of the world.

I took some shots of the scenery but coming back from a farm alongside a freshwater lochan spotted these tiny wee ducks in the reeds. They were hardly out of the water but they were diving back under and staying there for a very long time. I just could not get a good close up shot and I have no idea what they were. Thought I might be able to work it out when I came home, cropped my pics as much as I could to try and work it out, but I still have no idea.

On one of the pics it looks like it might have a bit of reddish colour round the side of the head. I didn't have a lot of time, much as I would have liked to stay there for the rest of the afternoon, we had to keep going. I will have to go back another day to try and identify. Would welcome anyones thoughts?

So bit frustrating but it just had to be my blip.