Baer's pochard Baer's pochard Baer's pochard ("Aythya baeri") is a diving duck found in eastern Asia. It breeds in southeast Russia and northeast China, migrating in winter to southern China, Vietnam, Japan, and India. The name commemorates the Estonian naturalist Karl Ernst von Baer. At , it is similar in size and stance to its close relative, the ferruginous duck ("A. nyroca"), although the coloration of the drakes (males) is entirely different. Baer's pochard males are similar to those of the greater scaup ("A. marila"), but have a dark back and upper flanks; the white lower flanks and belly are conspicuous. 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