Eastern rockhopper penguin Eastern rockhopper penguin The eastern rockhopper penguin ("Eudyptes chrysocome filholi") although genetically different is still often considered a subspecies of the southern rockhopper penguin. This species of penguin is also known to be one of the smallest species of penguins they are approximately 45–55 cm in length, and weighing 2.2–4.3 kg. The adult eastern rockhopper penguins feed on small fish, octopus, squid, and krill-like crustaceans. The rockhopper penguin "Eudyptes chrysocome" is sometimes considered two species, northern and southern rockhopper penguin, after research published in 2006 demonstrated morphological, vocal and genetic differences between the two populations. Molecular datings suggest that the
Bird-of-paradise lek-type mating system. Others, such as the "Cicinnurus" and "Parotia" species, have highly ritualised mating dances. Males are polygamous in the sexually dimorphic species, but monogamous in at least some of the monomorphic species. Hybridisation is frequent in these birds, suggesting the polygamous species of bird of paradise are very closely related despite being in different genera. Many hybrids have been described as new species, and doubt remains regarding whether some forms, such as Rothschild's lobe-billed bird of paradise, are valid. Birds-of-paradise build their nests from soft materials, such as leaves, ferns, and vine tendrils, typically placed in a tree