Is blue an unnatural color in nature?

I was told that blue was a mutated color in nature. But there are blue birds, blue jays and blue flowers. And I know that the color blue is a primary color that we need to make some other colors happen. We see the sky as blue because of color our eyes see in that area, so if there is so much blue that we see how is it unnatural in nautre?

Is blue an unnatural color in nature?
It is natural, however, not a basic color. Look at sky and sea: unnatural?

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