Australian Little Bittern Identification Guide

The Australian Little Bittern (ALB) could be considered the consummate skulker and lurker of our wetlands. It is not much larger than the small rails but, unlike them, it rarely comes out onto mudflats or into the open, preferring to remain within or on the edge of wetland vegetation. It occurs in diverse freshwater swamp habitats, mainly where tall rushes, reeds, Typha (cumbungi), shrub thickets or other dense cover is inundated by at least 30 cm of water. It can be found in vast swamps, but unlike the Australasian Bittern, it often inhabits small patches of dense wetland vegetation such as Typha along drains or in small urban lakes.

The ALB is the smallest Australian heron, only 35 cm long and weighing around 85 g. In contrast to most other herons, the sexes are distinguishable with the male having a black back, whereas the female’s back is brown. Both have a black or dark crown, a rufous or buff neck, black tail and a dark-brown double-stripe from throat to mid-belly, flanked by broader buff streaks. The juvenile is similar to the female except it has bold brown/black streaks on much of its body and rufous tips on most feathers feathers. In flight the male shows a marked contrast between dark back and primaries, and the buff upperwing coverts, whereas this contrast is reduced in the female and slight in the juvenile.

A migratory species in the southern part of its range, the ALB occurs locally across south-eastern and south- western Australia during spring and summer. Its status in northern Australia uncertain, but recent records suggest that some sites (mostly artificial) support a resident breeding population. More information is needed, especially in wetlands around the Ord River in Western Australia and in the Northern Territory and Queensland; some of the population winter in southern New Guinea.

Probably the best way of detecting this species at a wetland is by listening for their calls. Males utter a monotonous orrk-orrk-orrk , with notes uttered at 0.5 second intervals, in a sequence lasting about 10 seconds. Females are thought to give a call in a different pitch. Calls can carry at least 100 metres on still evenings. They are most vocal during the breeding season in spring and early summer, around sunset and sunrise, and they have been found to be much more vocal on warm, calm evenings (compared to cool windy conditions). Calls can be readily imitated by humans and often illicit a call-playback response from the birds – but this should not be over-used in case of disturbance to breeding birds.

Similar species

The small size and markings of the ALB are distinctive, but be careful to eliminate Striated Heron which lacks pale shoulder-patches, is larger (up to 50 cm long) and mainly occurs in estuarine and marine habitats such as mangroves.

In northern Australia, be wary of a potential vagrant species, the Yellow Bittern . This migratory species has been recorded once in Australia but may be go undetected. It is of similar size to the ALB, but it is a much paler bird, with both sexes being rufous brown on the back. However, in flight the primary and secondary feathers of all phases of Yellow Bittern are black and contrast markedly with the rest of the plumage, at times giving a piebald impression. Juveniles ALBs have rufous tips to the grey-brown primaries, secondaries and primary coverts and thus less contrast in flight; (see bird in hand below).

Distribution of the Australian Little Bittern from 1998-2011

Juvenile in hand. Note tiny size. Rufous tips Adult Female. Note yellow bill and general to flight feathers rule out Yellow Bittern paler colour compared with the larger (Mike Carter) Nankeen Night-Heron. It is very unusual for ALB to be out in the open like this (Neil Fifer)

Adult male in hunched pose. Note black back and crown, rufous hind neck and buff wing-patch (Tom Tarrant) Juvenile bird. Much more heavily streaked than adults (Mike Carter & Johnny Loy)

Confusion species

Adult (probable male) Yellow Bittern Compared to ALB, note longer, more slender bill, generally paler overall and lacking the dark double-strip down the throat and centre of breast (Andrew Sil cocks)