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Australasian Bittern

Australasian Bittern
Scanned image of medium format slide 
Australian Museum 
photographer: J. Fields
 
Introduction:

When disturbed, Australasian Bitterns disappear slowly into cover or blend into the surrounding reeds by keeping perfectly still with their neck and bill pointing skywards.

Identification:

The Australasian Bittern is a heavy-set, partially nocturnal heron with upperparts that are patterned dark brown, buff and black, and underparts that are streaked brown and buff. The eyebrow and throat are pale, and the side of the neck is dark brown. The bill is brown and the legs are greenish.
Colour: black & brown
Shape: generic heron, generic med-shore
Distinctive Features: Bill- prominent, curved and/or long
Markings: obvious streaks, spots and/or mottling

Size:

Large 66cm to 76cm

Similar Species:

The juvenile Nankeen Night Heron, Nycticorax caledonicus

Distribution:

The Australasian Bittern is found in coastal and sub-coastal areas of south-eastern and south-western mainlnand Australia, and the eastern marshes of Tasmania.

Habitat:

The Australasian Bittern frequents reedbeds, and other vegetation in water such as cumbungi, lignum and sedges.

Feeding and Diet:

Australasian Bitterns forage mainly at night on a wide range of small animals, including birds, mammals, fish, frogs, yabbies, snails, insects and spiders. LIke other herons, these birds use several techniques to capture prey, including: standing and waiting, slow stalking, and active pursuit. Wing and leg movements are used to confuse or attract prey items.

Communication:

Deep booming call, often at night.

Breeding Behaviours:

The Australasian Bittern has a regular season but will also breed during inland flooding. The nest is a shallow structure of dry or green reeds, within a clump of reeds in water or a swamp and is built on a platform of bent-over reeds. Several females will nest within one male's territory.
Breeding season: September to December
Clutch size: Four to six eggs

Conservation Status:

Drainage of swamps removes the habitat of Australasian Bitterns, but ricefields are also used by the species as habitat.