Bird ID please?

I am the first to admit that I know less than zero about birds, so please forgive me if this is a common/obvious one that I should know. We spotted this fellow whilst out on a walk with Fletch down beside a local river (more of a stream/burn/brook than a river really) and this was in quite a secluded area where the river was barely visible but there was a sort of marshy area.

 

Thanks

I am clearly even more of a non-birder then as to me it was 'a bird'

 

I doubt there will be any fish in the river (it really is small!) but we are pretty much surrounded by water so there is bound to be quite a lot of fish in the area - to give an idea, I have marked roughly where this was taken on the map...



You can't even see that wee river on there it is so small. This is a photo further downstream where it is quite a bit wider:

 

He loves them - we've got him on a really long lead too, so he can do a bit of exploring whilst we still have some safety