Swan Black (Cygnus atratus) adult, a migrant – Guernsey

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We came across the Black Swan in a field, note the white patch on its lower body.  This is the only indicator that its wings have a white trailing edge; see picture of it in flight.   The Swan is  native of Australia introduced in Europe and living in the wild in Guernsey. Thus I have classified it as a migrant rather than vagrant.