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 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