Southern rockhopper penguin first noted. Their breeding colonies are located from sea-level to cliff-tops and sometimes inland. Their breeding season starts in September and ends in November. Two eggs are laid but only one is usually incubated. Incubation lasts 35 days and their chicks are brooded for 26 days. Foraging behavior in penguins varies across ecological conditions. Rockhopper penguins are present at a variety of climates and locations; Amsterdam Island's (AMS) subtropical waters, Kerguelen Archipelago's (KER) subarctic coastal waters, and Crozet Archipelago's (CRO) subantarctic coastal waters. Due to the species plasticity they are able to express different strategies and foraging behaviors depending on
What Bird is That? according to their usual habitat. The accompanying text included brief notes on distribution, breeding and behaviour. While initial sales were poor, history tells us that Cayley had accurately discerned a market need and successfully responded to it. During WWII sales accelerated and Cayley’s first collection, reprinted time and time again, eventually became a household name among birdwatchers and the book was recognised as an Australian classic. The original sponsorship of "What Bird is That?" proved a great investment for the Gould League, who benefited from the sale of its numerous reprints and revised editions. By 1960, it was rated the