Bird of prey "Accipitres", subdividing this into four genera: "Vultur" (vultures), "Falco" (eagles, hawks, falcons, etc.), "Strix" (owls), and "Lanius" (shrikes). This approach was followed by subsequent authors such as Gmelin, Latham, and Turnton. Louis Pierre Veillot used additional ranks: order, tribe, family, genus, species. Birds of prey (order Accipitres) were divided into diurnal and nocturnal tribes; the owls remained monogeneric (family Ægolii, genus "Strix"), whilst the diurnal raptors were divided into three families: Vulturini, Gypaëti, and Accipitrini. Thus Veillot's families were similar to the Linnaean genera, with the difference that shrikes were no longer included amongst the birds of prey. In addition
What Bird is That? kookaburra seated on and within a large red question mark. It contains 36 coloured plates of paintings of Australian birds by the author, as well as several black-and-white photographic plates of habitat. There were numerous reprints and revised editions in various formats produced well into the 1980s. The first edition was sponsored by the Gould League of Bird Lovers of New South Wales of which Cayley was a Council member. In return for its sponsorship, Cayley offered the Gould League four tenths of his 10% book royalty. However, initial sales were slow and in 1935 he sold his entire share