are a product of quantum physics! WOW!!!! See, the thing is that, in all other birds, red feathers are a product of their diet BUT not for parrots. We have known that the red color in parrots is caused by psittacofulvin [notice the 'psitta' beginning of the word, indicating it belongs to parrots?] which is created in the liver [thus the red suffusion in birds that have advanced liver damage]. Well, now they have figured out that the pigment used for the red color is the same that is used for yellow BUT the molecules are closer in the red than in the yellow creating a smaller 'gap' between them which, in turn, changes the light wavelength so the color that is seen is not yellow but red. Now, I ask you, is that interesting or is that interesting?! I tell you, the more we learn about them, the more fascinating they turn out to be!
http://www.abc.net.au/news/science/2018 ... ry/9926294
https://phys.org/news/2018-07-scientist ... ather.html