Thursday, October 31, 2019
Wednesday, October 30, 2019
'A Polish type bird.' SC
Editors comments. I was not aware of a 'polish type' Mute Swan and asked Steve for more information, appended below. Thanks Steve.
The polish mute swan is a ‘pure white’ version of a mute swan. The legs and feet are a pinkish-grey colour instead of the usual black colour
A pigment deficiency of a gene in the sex chromosomes is what causes the whiteness.
When a female mute swan inherits only one melanin-deficient chromosome she will be a polish swan, whereas the male of the same parents will be normal. If the next generation is produced by two of their offspring the brood will contain numbers of both polish and normal cygnets of either sex.
Polish swans were given their name when they were imported from the Polish coast on the Baltic sea into London around about 1800. Mistakenly thought to be a new species they were given the name ‘Cygnus immutabilis’ (changeless swan).
Polish swans are not a different species of swan, because they are mute swans.
Posted by CBC at 2:48 PM