If you see a line of black birds flying somewhere in vee formation, chances are they'll be Little Black Cormorants. They occur all over Australia and Tasmania in suitable habitat - inland lakes and waterways, even right into the outback, they are quite common. They frequently gang together in a coordinated group to round up fish, as in the pictures below.

Breeding plumage (097207) is not very noticeable, just a few small white feathers on the crown and small plumes on side of neck.