Rockhopper penguin positions and islands became surrounded by subtropical water masses, resulting in a split between Northern and Southern rockhopper penguins. Many advance and retreat cycles of Patagonian icecaps during the late Pleistocene may have created a barrier to gene flow between Southern Pacific and Southern Atlantic populations, causing a split between Southern and Eastern rockhopper populations. Adult Rockhopper penguins have no land-based predators. They are eaten when at sea by leopard seals, fur seals, killer whales and blue sharks. Chicks and eggs are eaten by many birds including giant petrels, skuas, sheathbills and various types of gulls. Although the rockhopper penguin
What Bird is That? of "What Bird is That?" It was published in 1984 and incorporated all of Cayley’s paintings created over many years for his vision of releasing a “big bird book” and included a revised taxonomy. In the 53 years since its first edition, more than a hundred new bird species had been identified in Australia. Scientific names had been changed and groups of birds had been reordered. Lindsey brought "What Bird is That?" up-to-date with the latest birding conventions of the time, as well as contributing a valuable supplementary list of birds and a scholarly catalogue of Cayley’s paintings. The "Signature