478 THE LAW WHICH UNDERLIES PROTECTIVE COLORATION. 



Figure 1, of a ruffed grouse, shows this arrangement of color and 

 light. This bird belongs to the class in which the arrangement is 

 found in its simplest form, the color making a complete gradation from 

 brown above to silvery white beneath, and conforming to every slight- 

 est modeling. For instance, it grows light under the shelving eyebrow 

 and darker again on the projecting cheek. 



When he stands alive on the ground, as in figure 2, his obliteration 

 by the effect of the top light is obvious. 



Writers say •' he is so nearly like the color of his surroundings that 

 you can not see him." Figure 3 is to show that they ascribe the con- 

 cealment to the wrong cause. I merely took the bird shown in figure 2 

 and accurately tinted his under parts with brown to match his back, and 

 in less degree tinted his sides, till I had reduced him to uniformity of 

 color all over; but I did not, of course, change his upper surfaces at 

 all. In short, I extended his "protective" color all over him. 



Now observe the effect on replacing him in a life-like position. He 

 is completely unmasked. The reader has but to compare the distance 

 at which he can distinguish a bird in ISTo. 2 and in No. 3, respectively, 

 to see whether simple "protective coloration," as ordinarily defined, is 

 the true cause of this concealment, or whether this compound gradation 

 of color and light is the true cause. 



Figures 4 and 5 show that his colors are powerless to conceal him in 

 any position except the upright one which he holds when alive, and 

 figures 6 and 7 do the same for the woodcock. 



In figures 5 and 0, notwithstanding the fact that we have even the 

 strongest "protective" colors toward us, the bird is by no means 

 concealed. 



The woodcock sei-ies corresponds to that of the ruffed grouse. 

 Figure 8 shows a female on her nest, very difficult to find. In figure 9 

 the bird has been treated exactly as I treated the ruffed grouse in fig- 

 ure 3. Observe that she is essentially more conspicuous, though not a 

 feather of her ui)per parts has been artificially painted. The reason of 

 her visibility is that I have artificially extended her top colors down 

 her sides, thereby destroying her counter gradation and forcing her 

 solidity to manifest itself. 



