A young Straw-necked (left) and an Australian White Ibis
Australian White Ibis
White-faced Heron, equally at home in freshwater or tidal habitat. This is an adult.
And a juvenile.
There are couple of claims of this species on islands off the coast of Sabah, so it's one to look out for. The contrast between wing coverts and flight feathers, and the paler stripe on the underwing are two ways to distinguish it from a grey morph Pacific Reef Egret.