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 wren from such pairings. Males of several species pluck petals of conspicuous colours and display them to females for reasons unknown. The song of fairywrens is pleasant and complex, and at least two species (superb and splendid) possess, in addition to the alarm calls common to – and universally understood by – most small birds, another vocalization used when confronted by predators. This, termed "Type II Vocalization," is song-like and used when confronted by calling butcherbirds, and sometimes other predatory birds. Its purpose is, however, unknown; it does not seem to be a warning call. Australasian wren The Australasian wrens are