WCP4642

Dear Dr Wallace

This is the letter I refer to in which I go over this subject more clearly, to C. Hart Merriam the photographs referred to are the same I am now sending to you —¹

Yes, the enclosed photo’s[sic] show so exactly an over-whelming function of all top-whites in animals as to leave all signalling uses, etc. far down among secondary use ones. Just as when an animal shows his teeth, it is a very useful signal to beware of his biting, but it is because he is going to bite. Or when the wife hears her husband’s rifle, it is a signal that there will be venison for supper, but that is because he has shot a deer. In the same way the antelope’s expanding his white buttocks-patch may well give the alarm (when it is seen against a dark hill or wood). It would then give do the so alarm because other antelopes would have grown to associate its expansion with danger, merely because it automatically expands whenever the animal is pursued. But my photograph of the white card against the sky shows that white is the one color that will not show against the sky. Had deer, antelopes, big-horns and hares any color but pure white to expose for a rear view, as they bound away, especially in the twilight or night, the pursuer could catch sight, just as you and I would, of their receding form against the sky (or, if in the woods, against the patches of sky). These photos demonstrate that white, even in broad daylight, is indistinguishable against white.

[sketch of deer bounding at bottom of page]

(over)

[2] [sketch of bounding deer being chased by predator]

and what is wonderfully pat, every time the deer begins to gather for another leap her white is facing downward i.e. while it is low enough to relieve against dark.

Also, just as the white patches on forest birds, save perhaps oftenest in that shady place merely to pass for the lightest parts of the green near distance they being greened by the green light that pervades the place, so in

corresponding shades these white buttocks, tails or foreheads will pass for green distance.

Any artist will tell you that this is true expert testimony not theory.

[3] [sketch of fox chasing rabbit at top of page, which is numbered ‘2’ in type]

This fox sees the cotton tail against the sky (or rather does not see it!)[.] Strange that I am the first man to think to investigate how these white parts will look when seen from the level of the fox, wolf or cougar. As the skunk approaches his small prey, on the surface of the ground, he is saved from looming up dark against their sky, by having this ‘faked sky’ on his own body. See the photos! Even [h]is face-line of white appears a gap in the trees! Now this prairie skunk, the Texan ^(Conepatus), has commonly no trees in his background, and his white top imitates no tree-gaps, but gives a straight cut-off of all that would be liable to show, of him, above the sky line, from a grasshopper’s or mole’s standpoint!

Put a stuffed skunk skin out on the turf, lie down by it, and try this all, yourself. Of course, when the sky is white, instead of blue, is best, and in the night is best of all. Even the elk and red deer use a touch of this rear-guard-effacement and among our carnivora, all that are slow, scent-hunting grubbers, have more or less of this white effacement of the upper part of their heads, just what, from the mouse’s ground-stand-point, would show against the sky, and warn him in time. The badger, the oppossum and the ‘coon, and even a little, black-footed ferrett and in summer (?) the wolverine, — on his body, — all have more or less this skunk-like white. All these creatures I take it, need time to work up a scent, even when near the prey. On the other hand, foxes and cats, as you know, fling themselves high into the air, and come from on high upon their prey. ^{But they do this at the last moment and if they miss they will then look from low down at the retreating quarry, while from} above ^{its white doesn’t show.}

It boils down to this. Protective coloration is absolutely at full, all over the animal kingdom. For near by, with snake, quail, whip-poor-will, etc, it is the rotundity Nature most accurately disguises, (by the counter shading) but at a greater distance, and on such cases as the deer, jays, etc., all other possible means come into play. Yet all to the one end, viz. — to make the beholder seem to see through [4] [3 at top of page] the space occupied by the animal. The quail makes you think you see his background, where you really see him. So does the white buttock-patch. So does the white wing patch of many a Dendroica, jay or duck, ^{precisely on the principles shown in these photographs}.

Boys say, when they examine a dense brush heap, for bird or animal: "He isn’t there. I can see daylight right through, everywhere." ^{This is the very} gist ^{of the matter.} The white top, or wing-patch so common in birds does this daylight spot taking imitating, wonderfully, and when the wearer is in deep green shade, as a jay or rose-breast ^{oftenest is}, the green-yellow light converts these white patches to the note of lightest green distance in the woods ^{and thus, still makes the bird appear transparent}. So that you are liable to think you see this green distance, when you see, really, the bird. This is not theory, but a sight-expert’s revelation. All white, on animals, except the under-white, (whose function we ^already understand) is a wonderful representer of holes through the wearer. You see, especially in the woods, all openings out into the light [word deleted] are bright spots, and the background is such a patchwork of such holes, that of course a patchwork on the bird helps transform him to a picture of distance. In almost all cases, he is, of course, made, first, to appear unsubstantial by his counter shading, under all.

No one yet seems to take in that it isn’t a question of whether a hawk, (for instance) could see some disguised animal. The hawk element has forever ^long existed, amidst the world of animals and forever when his hunger had reached a certain pitch, he began to be tempted to try for some one of the animals in sight; and other things being equal, he would try for the one that he could see the most distinctly. Just as a man catching flies or butterflies will do. This is because he has learned that the birds are about as good at dodging, as he is at grabbing. That a hawk has difficulty, is shown by his alacrity to investigate an imitation ^{of the cries} of bird or mouse in distress.

This close balance makes all small advantages momentous, and explains the no doubt eternal increase of ^{quarry skill at} protective coloration, and [5] [4 at top of page] ^{on the other hand} of hawk power ^{and hawk-concealing coloration.}

I have photos that show a lot of other wonderful facts, but won[‘]t bother you now. I intend to send you, to show you, a winter view made all out of jay skins.

To return to the white-top case. Haven’t you and I stooped down, hundreds of times when out in the night, to try to get a glimpse of some animal, by bringing him against the sky? These white-tops, so long called warning colors, are the exact preventer of an animal’s being detected in that way, — and, by the way, what very poor thinking has been done about all this? The skunk’s white is, of course, only bright by day, and where is he, then? Down a hole! Also I often laugh to think how people talk about the tell-tale character of bright bird colors. Not one person out of hundreds that have looked at birds at large has ever perceived their bright colors till he got them in his hand. It takes the rankest of big color patches to be seen as color; at a small distance, a trogon, where he sits, is only perceptibly red, and no more so than his neighboring hollow tree-hole is by contrast to the green light.* And in the green, unifying forest light, Nature’s determination to cut birds up into apparent parts of the scene, require the utmost trogon-like contrast, anything to keep him from silhouetting in his real shape.

Yours always most gratefully,

P.S. I’m going to do a cheeky thing again, and bother you to return this letter. It may save me some writing, and my eyes trouble me.

[*]It takes perhaps, an artist to know this. So large an expanse of any color is required before it can be seen far, that a trogon’s red belly in green shadow ‘carries’ to the eye less far than the fainter reddishness, or say, than the red element in many ^{much larger} reddish expanses that abound in landscapes. I now believe that it is the dimness of tropical forests which may be the greatest factor in causing excessive brilliancy ^{of contrasting patterns} of birds & butterflies etc. as necessary, to cut them into pieces in so dim a light — this cooperating with the invitation to this development furnished by such patchwork background (over)

[6] In so dim a light, with, at the same time great diversity of background it takes the most excessive differences upon so slightly illuminated an object as a trog[o]n or toucan, to prevent his sli silhouetting in his true outline against every light patch. Because, by reductio ad absurdum, in the total darkness, he would be simply one black [letters crossed out] figure, no matter what his pattern, and no matter how bright the distant ^light-loop holes against which he might be seen[.] In the woods things are all dark against the vistas up and out into the light.

You will be surprised to find how slight a difference of level of beholder’s eye, relative to the white surface beheld makes the whole difference as to seeing it against earth or sky even who amidst trees.

I am very sincerely yours with the most ardent wish to repay you for all you have been to me and my son too, all my life.

Abbott H Thayer [signed]

May I ask you to greet your daughter, for me and my son?