I think beauty, by it’s nature, is not a quality of the observed, but of the observer. It is not the stimulus that is beautiful, it is the sense of pleasure that is perceived.
Looking at that peacock, and the bird, reminds me that I have never seen a clash of colors in nature. In fact, the colors on that bird are so perfectly complimentary that you could not do better if you had a color wheel in your hand. This tells me that beauty, at least when it comes to color selection, is an objective reality.