APPENDIX E 
493 
cape observation, and its coloration and squatting attitude enabling it 
thus to escape observation; as Mr. Beddard puts it in his book on “Ani¬ 
mal Coloration/’ “absence of movement is absolutely essential for pro¬ 
tectively colored animals, whether they make use of their coloration for 
defensive purposes or offensive purposes.” So far as Mr. Thayer’s book 
or similar books confine themselves to pointing out cases of this kind, and 
to working on hypotheses where the facts are supplied by such cases, they 
do a real service. But it is wholly different when the theory is pushed 
to fantastic extremes, as by those who seek to make the coloration of 
big game animals such as zebras, giraffes, hartebeests and the like, pro¬ 
tective. I very gravely doubt whether some of the smaller mammals 
and birds to which Mr. Thayer refers really bear out his theory at all. 
He has, for instance, a picture of blue jays by snow and blue shadow, 
which is designed to show how closely the blue jay agrees with its sur¬ 
roundings (I would be uncertain from the picture whether it is really blue 
water or a blue shadow). Now it is a simple physical impossibility that 
the brilliant and striking coloration of the blue jay can be protective 
both in the bare woods when snow is on the ground and in the thick 
leafy woods of midsummer. Countless such instances could be given. 
Mr. Thayer insists, as vital to his theory, that partridges and other pro¬ 
tectively colored animals owe their safety, not at all to being incon¬ 
spicuously colored, that is, to being colored like their surroundings, but 
to their counter-shading, to their being colored dark above and light 
below. But as a matter of fact most small mammals and birds which 
normally owe their safety to the fact that their coloration matches their 
surroundings, crouch flat whenever they seek to escape observation; 
and when thus crouched flat, the counter-shading on which Mr. Thayer 
lays such stress almost, or completely, disappears. The counter-shading 
ceases to be of any use in concealing or protecting the animal at the precise 
moment when it trusts to its coloration for concealment. Small rodents 
and small dull-colored ground birds are normally in fear of foes which 
must see them from above at the critical moment if they see them at all; 
and from above no such shading is visible. This is true of almost all the 
small birds in question, and of the little mice and rats and shrews, and 
it completely upsets Mr. Thayer’s theory as regards an immense pro¬ 
portion of the animals to which he applies it; most species of mice, for 
example, which he insists owe their safety to counter-shading, live under 
conditions which make this counter-shading of practically no consequence 
