The White-necked Heron Ardea pacifica is an occasional visitor to the Goulburn Wetlands. It is also called the pacific Heron, which is rather inaccurate, since its home range is mainly throughout Australia and occasionally reaches the nearest island nations (Indonesia, Papua New Guinea and new Zealand).
It prefers to be near shallow fresh water of almost any kind, from extensive ponds and lake shallows to farm dams, wet grassland, garden fish ponds and even puddles in the road. White-necked herons will occupy a wide range of habitats of this quality, but really are specialist hunters of drying waters where small animals are concentrated in ever diminishing spaces. They will eat just about any small water animal they can catch, from water insects, shrimps and yabbies to frogs and fish. To do this they walk very slowly though the water or will wait until prey passes by.
Like other herons and egrets white-necked herons possess a double-curved or s-shaped neck. This is due to a specialised 6th vertebra that makes its neck hinged. This allows all herons and egrets — unlike other waterfowl such as ibises, spoonbills and storks — to fold their long neck out of the way when they’re resting or flying. If you see a large bird flying overhead with its head tucked back then you know it must be a heron or egret. Another advantage of having a hinged neck is that it provides considerable momentum. Herons have a sharp, stiletto-like beak that allows them to spear their prey and to do that they have to act with lightning speed. The hinged neck acts like a spring mechanism, allowing the neck to very quickly go from being in a folded position to being fully outstretched. So, as soon as a heron focuses its eyes on prey it can unleash its steel-trap like neck in an instant. There is of course a price to pay for this. In order to hunt in this way herons have to be firmly anchored to the ground or a branch, which restricts them to being waders or stalkers of wet paddocks and long grass.
White-faced herons can form flocks of up to several hundred birds in ideal conditions, but generally they are seen alone. Although they get on with other species of water bird quite peacefully, they will guard their feeding territory from others of their own species.
Like other herons and egrets they roost and nest in trees. Sometimes they will nest in loose colonies with other white-necked herons but more usually they prefer to breed alone.
White-necked herons, like other herons, fly slowly and gracefully with slow wing-beats. Their legs are held out straight behind them in flight. They are usually silent but, also like other herons, will croak or grunt. They have white strips along the leading edge of their wings.
When breeding, adult herons are jet black with pure white heads and necks. Their breast becomes maroon coloured. Outside the breeding season they lose this colour and their necks are more off-white, usually with a double row of spots along the front of the neck and have black streaks on their bellies. Young birds are even less pristine, with grey wings, backs and tails. They have greater numbers of and more noticeable spots on their necks, which tend to be a very dirty white or even buff in colour.