Musk Ducks After visiting Aldinga Scrub CP last week we decided to call in to the Hart Road Wetlands on the way home, to check out the resident male Musk Duck. He was still there, & after watching him for a while I started to ponder on why his tail feathers sometimes appear to be a blue colour when spread out in the water. I was reminded of the time we visited W.A. in September 2019, staying at the Karri Valley Resort, SE of the Margaret River region. The Resort is on a lake fed by water from the Beedelup Falls (and incidentally is a great place to stay). There were a number of Musk Duck there, including the female shown in the photograph, which also was showing blue tail feathers. After puzzling about this for a while I eventually remembered one of the WEA lectures given by Joan Paton, (which I attended last century!) when she told us that the blue colour of birds is not from actual pigments. It is created by the way light waves interact with the arrangement of their keratin molecules in the feathers, and which reflect light in subtly different ways to produce different shades of what our eyes perceive as the colour blue. Since all the feathers of Musk Ducks appear to be grey some of the time, and only blue when we see them from certain angles in the water, I assume that refraction of the light rays in the water makes them appear blue to us. I have not been able to find any published work on the particular subject of whether this is relevant to Musk Ducks, so I might be completely wrong, but it’s the best I can think of! (Googling directed me to a relevant article by Scott Sillett, a wildlife biologist at the Smithsonian Migratory Bird Centre, entitled Colour of Feathers in Birds.)
2 Comments
Rosemary
7/5/2020 09:25:46 am
That's really fascinating Margie and the photos show the blue beautifully.
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Margaret Tiller
8/5/2020 03:00:18 pm
Thanks Rosemary, this is something which has puzzled me for some time, so the Blog made me follow it up!
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