Hello. I saw this bird today on the Brecon & Monmouthshire canal at Gilwern. Can you identify it? And is it a duck or a goose? Not the mallards, obviously...
I would say it's a grey variant of a Muscovy Duck - probably female. See HERE - scroll down for a good match with your bird. Although there's a lot of variation because they've been domesticated over many years they all have the characteristic red skin near and around the eye.
I'm tempted to go for Muscovy duck.
For me, the size in relation to the mallards plus the red around the eye suggests that.
If I'm wrong, someone will point us in the right direction.