Rockhopper penguin reaching full growth, they are about 20 inches in height. Males and females cannot be distinguished just by looks, so a DNA test is conducted by taking a feather from the bird to determine its gender. Like many penguins, rockhopper penguins have a white belly and the rest of their body is black. Some characteristics that differentiate them from the other penguins are their red eyes, orange beak, pink webbed feet, and the yellow and black spiky feathers they have on their head. Although their yellow and black spiky feathers differentiate them from other penguins, rockhopper penguin chicks do not
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