Moderately common around freshwater swamps in the north, elsewhere uncommon.
Habitat
Terrestrial wetlands, and estuarine and littoral habitats. Freshwater springs, rivers and creeks within or fringed by rainforest or woodland. Forage at edge of running or still water.
Voice
A loud, deep, drawn out, booming, 'whooom, whooom', at intervals of 10 - 20 seconds. Also soft, moaning sounds, soft, low, hissing, and a repetitive 'e-eh, e-eh' is uttered at the nest.
Nest
A small, flatish, unlined structure composed of sticks, twigs and reeds with a shallow depression on top, set on a foundation of coarser sticks, on a horizontal branch of a thick leafy tree, overhanging water.
Eggs (Guide)
Up to 6; slightly glossy, bluish-white; rounded-oval; about 44 x 35 mm. Incubation: by both sexes.
Young
Semi altricial, semi-nidicolous.
Subspecies
The following 3 subspecies are recognised:
flavicollis (Latham, 1790) - South-eastern Asia from Pakistan to south-eastern China and south to Indonesia and Philippines.
australis (Lesson, R, 1831) - Moluccas, New Guinea and Bismarck Archipelago south to western, northern and eastern Australia.
The Field Guide to the Birds of Australia Pizzey, G., and Knight, E., 1997, Angus & Robertson, Sydney ISBN 0 207 19691 5
Field Guide to Australian Birds Morecombe, M., 2000, Steve Parish Publishing Pty Ltd. ISBN 1 876282 10 X
Field Guide to the Birds of Australia Simpson, K., and Day, N., 1999, 6th Edition, Viking ISBN 0 670 87918 5
Reader's Digest Complete Book of Australian Birds 1988, 2nd Edition, Reader's Digest ISBN 0 949819 99 9
What Bird is That? 1984, Revised Edition, Angus & Robertson, Sydney ISBN 0 207 14846 5
Handbook of Australian, New Zealand & Antarctic Birds 1990 - , Oxford University Press, Melbourne ISBN 0 19 553244 9
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BirdLife International Species Factsheet