Towards the end of June my camera and I went on a train from Vauxhall station to Barnes Bridge. I walked through Barnes village on my way to the Barnes Wetland Centre. In the centre of Barnes there is a pond. On the pond was a family of Mute swans - two adults and five juvenile cygnets. There were three white cygnets and two brown cygnets (the usual colour of cygnets).
Here an adult swan is in a bit of a flap behind 1 brown and 2 white fluffy cygnets.
Two of the lighter coloured cygnets were swimming in a line.
It was bath time, so all the cygnets were looking a little scraggy.
The more normal coloured cygnet is in the front of this photograph.
After I had been to the Wetland Centre, I walked past Barnes pond again on my way back to the station. The cygnets had dried off by this time and were looking a little fluffier.
Last year the Barnes pond swans also had a couple of white cygnets as well as the normal light brown cygnets.
I believe that white cygnets are called "Polish" mute swans. I took the following information from the internet:
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.
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