A few more than ten years ago the word camouflage became part of our vocabulary. Ships, guns, and men were concealed by various devices including schemes of coloring. As a new and foreign word it needed definition. What better synonym could have been offered than the term "protective coloration"?
Nature had long since learned the value of camouflage and had clothed the animals so for their protection. Many examples among insects may be readily called to mind and the concealing coloration of the ground-dwelling birds, such as the Grouse and Nighthawk, is familiar. Whether the same principle can be applied to all birds, including those of brilliant colors might be of some question. We must remember however that the birds are not colored to be protected from us. We have, to some extent, become enemies of theirs, but they were not adapted for that contingency. We must interpret their coloring as far as possible in terms of how their enemies see them or how they see their enemies.
Photographs of birds seem to render them conspicuous, since any value their color may have is lost except in just such cases where both bird and background are comparatively colorless. Specimens mounted against plain backgrounds naturally appear brillialt by contrast; and even when in habitat settings the individual bird is conspicuous. But when we consider the multitude of colors and shades of colors provided by Nature as a background we cannot be so positive but that brilliant plumage of a bird may have protective value. A camouflaged ship, painted in streaks and stripes and patches of all conceivable hues, when at the dock in harbor, was certainly not concealed -- nor was its position, shape and bulk deceptive. But it was not colored for such a situation. Upon the open seas it was not concealed by its colors, but its shape and direction of progress were rendered deceptive. This was not true of a ship painted in uniform "battle-ship grey", since, - though in part concealed by its color - when once observed all else concerning it was obvious. Deceptive coloration then would seem to include not only those factors which would conceal the bird, but also those which would deceived its enemies in other ways.
Another point is that the coloring of almost all animals is based upon a principle of shading, the upper surfaces being darker, the lower surfaces lighter. Light falling upon the upper surfaces renders them lighter in appearance and naturally the shadows fall upon the lower surfaces rendering them darker, thus blending the two extremes and making the scheme uniform. An inanimate object can be seen because of differences between light and shade. Are living creatures actually less conspicuous because they are colored to counteract this? Do we see a tuft of grass or a rock because of its shadows but fail to see the ptarmigan because we see "through" it as though it were a flat surface?
When we consider birds in their natural habitats we realize that on a broad basis their colors do blend with their environment. Sea birds are grey or white as in gulls or terns and when contrasts do appear these are not often in brilliant hues, and they may have the same significance as the contrasts of a camouflages ship. Ducks such as the Mergenser, seen occasionally upon the lakes of Mt. Rainier, have marked contrasts in color. Though the Mergensers and the Harlequin Ducks have marked contrasts in color and are obvious to our eyes, but do not these odd and striking markings blend in nature with the colors and reflections and glints of light on the waters where the live? Or, when in their more typical habitat upon a rocky shore do their contrasts "break" them and alter them as did the camouflage of ships?
Earl U. Homuth,
(Note: The second portion of this article on bird coloration will appear in the next issue of Nature Notes.)
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