Australasian Bittern Botaurus poiciloptilus Australasian Bittern. Photo: John Gitsham Bitterns are secretive and superbly camouflaged, and so often remain undetected in their preferred habitat of reeds and rushes. They give themselves away, though, by deep, resonant booms uttered two or three times at 1-2 second intervals. Australasian Bitterns are rare and rated as ENDANGERED in Australia. Australian Bitterns prey on a wide variety of aquatic animals – fish, crayfish, amphibians (particularly frogs), crustaceans, snails, insects and other arthropods, small mammals (rats and mice) and even birds such as silvereyes (Zosterops). They forage by standing still, or quietly stalking, and then striking suddenly with the bill. They have been recorded using small bits of grass as bait to lure fish. Australasian Bittern. Photo: John Gitsham The bitterns nest is a thin platform of rushes or reeds just above the water but may be constructed of grasses and situated far from water e.g. in rice paddies. There are normally 4-5 eggs in a clutch, which is laid from late August to late December, with the nestlings appearing between late September to early February. The female alone builds the nest, incubates the eggs and feeds the chicks. Bitterns are usually monogamous but males may have more than one female. Description The Australian Bittern is a large, heavy-set heron, with a thick neck and heavily streaked brown and buff plumage, which blends perfectly into the reedbed background. This camouflage is enhanced by the habit of freezing in an erect posture with the bill pointing skyward. The position of the eyes is diagnostic. They are placed so that the bird can still see towards its front while the bill is in the freeze position. The hindneck and upperparts are usually dark brown but may range from near black, through chocolate, to rufous. The underparts are whitish, or a pale buff and are heavily streaked brown. Males and females are alike except that the male is up to twice the size of the female. The bill is yellow or yellow-buff, with a dark culmen ridge. The iris is yellow to orange-brown. The facial skin is green-grey, and the legs are dark olive. Immatures are paler than adults but otherwise similarly marked. Where to find it Bitterns are to be found in wetlands having tall reedbeds composed of reeds (Phragmites), sedges, rushes and cat tails (Typha). They prefer still water with little fluctuations in level. They may also be found in wet paddocks with long grass, and in rice paddies, where they may breed. They are basically sedentary but move in response to extremely dry or wet conditions. In South Australia, they may be found in suitable habitat east and south of the Fleurieu Peninsula. Australasian Bitterns are monotypic, having no subspecies. They are rated as ENDANGERED in Australia and VULNERABLE in South Australia.