Volume 4 of HANZAB covers 119 species, of which 107 breed in the region. They include some of the most spectacular birds found in HANZAB, such as cockatoos and cockatriel; parrots, fig-parrots, rosellas and lorikeets; cuckoos and koels; owls; barn owls; frog mouths; nightjars; goatsuckers ornighthawks; owlet-nightjars; swifts; kingfishers; bee-eaters; dollarbirds. The information is presented in sections; field identification, habitat, distribution and population, movements, food, social organization, social behavioura, voice, breeding, plumages, and external morphology. The accountsinclude black and white illustrations of behavioural postures and plumage features, maps showing breeding and non-breeding distribution, sonograms of calls and songs, and diagrams of timing of breeding and moulting. The accounts conclude with a full list of references.