Though other herons may occasionally visit the island, the only member of the Ardeidae which is a breeding resident is the eastern reef egret. And even though the terms "heron" and "egret" are not scientific, the former is generally used to denote the large "Ardea" whereas the smaller "Egretta" species are usually called "egrets". Insofar, the only "true" heron that could ever be found on Heron Island is the white-necked heron ("Ardea pacifica"), which is only seen every now and then as a rare vagrant.