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 vocalization and prevent an energetically costly fight . In birds with song repertoires, individuals may share the same song type and use these song types for more complex communication. Some birds will respond to a shared song type with a song-type match (i.e. with the same song type). This may be an aggressive signal, however results are mixed. Birds may also interact using repertoire-matches, wherein a bird responds with a song type that is in its rival's repertoire but is not the song that it is currently singing. This may be a less aggressive act than song-type matching. Communication through bird