On reading my books and a bit of googling I find there are a few possible explanations.... one being known as a "Polish Swan", which has pink legs and feet. The morph immutabilis ("Polish Swan") has pinkish (not dark grey) legs and dull white cygnets. (Wikipedia).
I don't have any photos that show the legs so that's a target for later in the week.
The other possibility is that it has a leucistic gene.
On checking an earlier photo dated 6/6/2013 I now question whether one of the cygnets was whiter than the others on that occasion. Had I risked a better camera in the kayak then I may have been able to answer that question!
|2 months ago when the cygnets were first introduced to the river, is the one nearest the Penn.|