This is half of one color plate from a book intended to show how “showy” coloration can actually make some creatures harder to spot in their natural habitats.
This is a male wood duck, as sketched in color by Abbott H. Thayer. He explains:
These paintings show one of the very common situations in which the boldest contrasts of a male Wood Duck’s coloring come into play in preventing his showing his silhouette.
His dark areas, with all their varied colors, here ‘become a part’ of the like-colored dark reflections in the water, and his white patterns exactly reproduce the bright sky-reflections, so that he is so to speak ‘dissolved’ into the scene. — A. H. T.
The book is called Concealing-Coloration in the Animal Kingdom: An Exposition of the Laws of Disguise through Color and Pattern and is mostly written by Gerald Thayer, Abbott’s son, about his father’s theories of camouflage. The elder Thayer (and his gifted painter’s eye) won quite a few admirers for his ideas, but he took them a little too far, crediting the need for camouflage with nearly every element of evolutionary pressure. “Our book presents, not theories, but revelations, as palpable and indisputable as radium or X-rays,” he declared.
The whole book can be browsed on archive.org, but I first came across it in a brief but fascinating write-up on The Public Domain Review.