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 tracks in the field using a handheld palm pilot and GPS system that streamlines the collection process. This free program is called CyberTracker. In order to make sure that data is reliable, a tracker evaluation system has been put in place through the CyberTracker organization. Bird tracks Bird tracking provides a way to assess the habitat range and behavior of birds without ever seeing the bird. Bird tracking falls under the category of tracking and is related to animal tracking. A guide to bird tracking has been published. Bird tracking is a tool used by naturalists to assess what birds are