Southern boobook smallest owl on the Australian mainland, the southern boobook is long. The nominate subspecies is the largest. It has short, rounded wings and a short tail, with a compact silhouette in flight. Southern boobooks on the Australian mainland follow Bergmann's rule, in that birds from cooler and more southerly parts of the range tend to be larger. Thus, birds from the Canberra region weigh around while those from the Cape York Peninsula and Broome are around . Females tend to be a little larger and heavier than males, with males weighing and females . The southern boobook has generally dark
Australasian Hydrographic Society and gas industries, particularly off the north west coast of Western Australia and coal export facilities in Queensland have required a considerable increase in the provision of accurate and up to date hydrographic information. The attendant increase in trade, for example, has made improved navigation through sensitive area, such as the Great Barrier Reef critical. Hydrography also plays an important role in national security, border protection and humanitarian support. The Australasian Hydrographic Society endeavours to represent all interests in these domains. The Australasian Hydrographic Society consequently "aims to serve anyone with an interest in the science (and art)" of hydrography,