Black Swan

Black Swan (Cygnus atratus) is a large Australian swan with mostly black plumage, white flight feathers and a bright red bill. The combination of body shape, bill structure, plumage pattern and voice provides the most useful field characters. Age, sex and season can alter its appearance, so identification should use several features rather than colour alone. This supports comparison with similar species in the field (Wikipedia, general species account).

It feeds on aquatic vegetation in lakes and wetlands, with both members of a pair sharing incubation and cygnet care. Its movements and social behaviour vary through the year, with breeding birds generally more dispersed and non-breeding birds more likely to gather where food is concentrated. Japanese records place it within the country's documented avifauna as a resident, migrant, visitor or introduced bird (Wikipedia, general species account; Wildlife of Japan occurrence records).