Nankeen Night Heron Nycticorax caledinicus Nankeen Night Heron, adult. Photo: John Spiers Night Herons are gregarious birds. During the day they congregate in large groups in the canopies of trees from which they fly out at dusk giving sporadic croaks, to forage until dawn. Nankeen Night Herons have a catholic diet. They eat fish, a variety of small vertebrates (amphibians, chicks and eggs of other birds, small mammals such as mice, crustaceans, arthropods of various kinds particularly aquatic insects, and human rubbish. They tend to forage alone using passive techniques such as standing and walking slowly but are sometimes more active, capturing prey by feet first diving. Swimming or attracting prey by vibrating their bills in the water. Prey is caught with a quick jab of the bill. Foraging is done from dusk to dawn, but when feeding chicks it may also be done during the day. Nankeen Night-heron, juvenile. Photo: John Spiers Breeding usually occurs in the summer months from October to March, but timing may be affected by rainfall and its impact on food availability and water conditions. Nankeen Night Herons are highly gregarious and will form colonies of 250 pairs or more. They tend to remain apart from other colonial nesters such as other herons, spoonbills, cormorants and ibises. They nest in trees or large bushes. Their nests are made of sticks lined with leaves. They are normally single-brooded with a clutch of 2-3 green-blue eggs. The sub-species found in Australia is Nycticorax caledonicus australasiae (Vieillot, 1823). Description Nankeen Night Herons are short and stocky, medium sized herons with a thick neck. They have a distinctive black cap, a rufous to dull brown (nankeen) back and wings, and a white belly. The underwing is white, the eyes are yellow and the lores and facial skin greenish yellow. The legs and feet range from bright yellow to dusky ochre-yellow. In breeding plumage two to three nuchal plumes raise from the crown, the legs can be bright pink, the lores become blue and the iris red. Male and females are alike except that the female is slightly smaller. The juveniles are heavily spotted and streaked grey-brown. The bill is grey-black with yellowish cutting edges. The eyes are yellow, the bare facial skin is yellow-olive and the legs and feet lime-green to olive-grey. Where to find it Nankeen Night Herons are found in a range of wetlands with forested margins whether freshwater, brackish or marine e.g. swamps, lakes, pools, slow-moving rivers, mangroves or inlets of the sea. They are moderately common in suitable habitat on the Adelaide Plains, along the Murray River and around the lower lakes, but are uncommon elsewhere in South Australia. They are usually sedentary, but they may move in accordance local water supply e.g. within the Murray-Darling basin.