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
Anatomical terms of bone a condyle, particularly the medial epicondyle of the humerus. These terms derive from Greek. An "eminence" refers to a relatively small projection or bump, particularly of bone, such as the medial eminence. A "process" refers to a relatively large projection or prominent bump, as does a "promontory" such as the sacral promontory. Both "tubercle" and "tuberosity" refer to a projection or bump with a roughened surface, with a "tubercle" generally smaller than a "tuberosity". These terms are derived from "Tuber" (). A "ramus" () refers to an extension of bone, such as the ramus of the mandible in the jaw