Sorry for the poor pics but they just kept circling and wouldn't land. A bit of a struggle for my camera.
No interactions present.
Please click on "view original" for the silouette shot. Or you won't see the birds, just the gap in the middle.
I'm not sure a definite answer can be given to these birds, from the pictures provided. The bill looks quite heavily based in the silhouetted picture, which might suggest Goosander; but that picture also shows a suggestion of a dark line across the white wing square, suggesting Red-breasted Merganser. I'd leave it at Mergus. The location, incidentally, would strongly suggest R-b M as the likely species. Overall, I tend to agree with you, but see what others think...
My Flickr photos...
In the first picture, although blurred, there is a noticeable border
between the darkish head and the pale neck, which would indicate
Goosander rather than Merganser. A tough one to call though, so Mergus it is..
Agreed about the head/neck.
But then look at the head and neck on the far bird in this picture...
It was frustrating as they were so close but flying circuits round very fast. They seemed to be weighing up whether to land on the sea or the salt water pool. I was sat on the beach between the two.
I wish I had a more experienced bird watcher with me at the time.
As you've shown interest I've added another picture - still blurred but it might help.
Having had the luxury of looking at the additional fourth image, I think they may be Red Breasted Mergansers. The front bird looks like a female with a white speculum and the rear bird looks like a male with a brown / red breast.
What do you think ?
Chris Brooks - www.dragonfly-images.co.uk
My Flickr site - www.flickr.com/photos/ceb1298
Lat/Lng: 51.978, 1.3869
OS grid ref: TM326364