There are usually a lot of Cormorants in the sea, but if you look carefully, some of these are actually Shags. Shags are slightly smaller, and all over black (with a green sheen). They have thinner beaks, with a small bright yellow patch at the base of the beak. The head shape is more rounded and they can sometimes have a crest on the top of their head. In Druridge Bay, they always seem a bit far our for a good photo unfortunately.

One interesting difference is they way they dive. Cormorants just sink, like a submarine, but Shags will arc upwards to dive so that you can see daylight underneath as they go under.

The photo below shows a raft of five Shags out at sea. The one on the far left clearly has his crest starting to grow...