Common pochard mainly due to urbanization of the natural habitats and their transformation, as well as due to overhunting. The pochard is one of the species to which the "Agreement on the Conservation of African-Eurasian Migratory Waterbirds" (AEWA) applies. Common pochard The common pochard (; "Aythya ferina") is a medium-sized diving duck. The scientific name is derived from Greek " aithuia" an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin "ferina", "wild game", from "ferus", "wild". The adult male has a long dark bill with a grey band, a red head and neck, a black breast, red eyes and
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