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
A Bird came down the Walk other evil forces.Then the narrator offers the bird a piece of crumb,but the bird neglects it and then it flies away. Helen Vendler regards the poem as a "bizarre little narrative" but one that typifies many of Dickinson's best qualities. She likens the poet to a reporter observing a murderer in the act, and later, pretending fear that the murderer may be dangerous to herself and must be mollified by a "crumb". The bird takes flight and Vendler regards what follows - the description of the bird in flight - as "the astonishing part of the poem". Vendler notes that