Greater scaup been described by Serebrovskij in 1941 from fossils recovered at Binagady, Azerbaijan. The greater scaup's name may come from "scalp", a Scottish and Northern English word for a shellfish bed, or from the duck's mating call: "scaup scaup". A phylogenetic analysis of the diving ducks, examining the skeletal anatomy and skin, found that the greater and lesser scaups are each other's closest relatives, with the tufted duck as the next closest relative of the pair. The adult greater scaup is long with a wingspan and a body mass of . It has a blue bill and yellow eyes and is
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