No interactions present.
It looks to be a mixed flock, with the birds at the rear being Shag, and odd others scattered through the flock.
Generally, I would expect a flock this big, off the West coast, to consist mainly of Shag.
My Flickr photos...
I concur with the above comment by Ophrys but the majority seem to be Cormorants and therefore I have agreed with the identification.
Chris Brooks - www.dragonfly-images.co.uk
My Flickr site - www.flickr.com/photos/ceb1298
Both species appear to be present.
At last some decent weather on the west coast after a long wet winter - great to see the sunshine on the Glenelg shore!
Lat/Lng: 57.222082933351, -5.6745457649231
OS grid ref: NG782205