Northern rockhopper penguin Island in the south Atlantic Ocean. The rockhopper penguin was split into three distinct subspecies in 1992; the southern, ("E. c. chrysocome"), eastern ("E. c. filholi") and northern rockhopper penguin ("E. c. moseleyi"). The three subspecies are distinguished by differences in the length of the tassels of the crests, the size and colour of the fleshy margin of the gape, colour pattern on the underside of the flipper and differences in the size of the supercilliary stripe in front of the eye. Additionally, the northern rockhopper penguin is larger than the other two subspecies. Proof that the three subspecies were
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