Southern rockhopper penguin the last thirty years. This decline has earned them the classification of a vulnerable species by the IUCN. Threats to their population include commercial fishing and oil spills. With the approval of the European Association of Zoos and Aquaria (EAZA), Drusillas Park in East Sussex holds the studbook for rockhopper penguins in Europe. Zoo manager Sue Woodgate has specialist knowledge of the species, so the zoo is responsible for co-ordinating the movements of penguins within zoos in Europe to take part in breeding programmes and offer their advice and information about the species. Rockhopper penguins are the most familiar of
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