Australasian Gannet
Morus serrator

One of two gannet species that occurs in Australian waters (the other being the much rarer Cape Gannet). As with all gannets, they look for fish from a height and on spying some, they dive at great speed into the water. The first two are adults and the third is a juvenile.
 

1-2: South Pacific, off Sydney, 13/03/2010.