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
Bird netting of a barrier to their diving into the ponds. Bird netting is one of the most effective and long lasting ways of bird proofing buildings and other structures against all urban bird species. It provides a discreet and impenetrable barrier that protects premises without harming the birds. Bird netting can be particularly effective for large open areas such as roofs and loading bays. Design considerations include the type and material of the fixings utilized and the bird species requiring exclusion. Miners will use chemical agents to extract minerals or metals from crushed rocks. These harmful chemical agents must be confined