Raft of Ninety-Seven

I was on a low cliff watching the shore birds (eider, curlew and heron) when I became aware of a huge raft of sawbills cruising past just offshore.
In fact there were 97 mergansers ( Mergus serrator) in the raft and they were making surprisingly fast progress along the shore.

An extreme telephoto of a few of them is posted as an 'extra'