A rare sight

The Kotuku or large white heron is a rare bird (estimated to be about 200 in NZ ), l was lucky enough to see it whilst photographing Spoonbills. It is quite large and very statuesque slowly, and precisely catching it's supper.
My understanding Is that this one may be ready to breed as it's beak is black rather than yellow and if you look hard, at the rear, you will see it has some wispy, lacey feathers.