burroughs] PROTECTIVE COLORS OF ANIMALS 161 



tective, then bright colors are non-protective or dangerous, and 

 one wonders why all birds of gay feather have not been cut off 

 and the species exterminated." 



Second, neutral concealing tints are protective from the point 

 of view of the human eye, but many of the most destructive pre- 

 daceous animals depend upon scent to locate their prey. Birds 

 of prey are not fooled by color disguises. White rabbits are con- 

 cealed on snow and gray ones are conspicuous, but where is the 

 advantage since their natural enemies — foxes, minks, weasels, 

 owls — hunt at night ? There are numerous similar facts which 

 make us feel decidedly uncertain concerning this phase of the 

 color theory. 



Aggressive coloration (concealment from prey) is also capri- 

 cious. ' Why should the owl, which hunts by night, be colored 

 like a hawk which hunts by day?" "The lion is desert colored 

 too. Is this for concealment from its prey? But it is said that 

 horses and oxen scent the lion long before they can see him, 

 as doubtless do the wild creatures of the desert upon which he 

 feeds. Their scent would surely be keener than that of our 

 domesticated animals, and to capture them he must run them 

 down or ambush them where the wind favors him." 



Warning colors or danger signals are likewise variable. The 

 skunk's contrast of black and white is said to be of warning 

 value ; but why does the porcupine, who is able to compete with 

 the skunk in making life disagreeable for his attacking enemies, 

 not have warning colors also? 



Concerning concealment of nesting birds and their nests, Mr. 

 Burroughs thinks that this is not for the sake of the mother 

 birds, but for the sake of the eggs or helpless unfledged young. 

 The obscure color of the female tanager, cardinal and similar 

 birds plays no part in protecting her from crows, weasels, hawks, 

 etc., which explore trees looking for young birds. The enemies 

 of the ground builders hunt at close range and capture, not the 

 nesting female, but the eggs and young. 



Materials for nests are not chosen for protective colors, as we 

 have fancied. Anyhow, could marauding crows, jays or squirrels 

 be deceived by nests which to our eyes seem to be protectively 

 colored ? 



The brilliant colors of many males are, according to Darwin's 

 theorv of sexual selection, to be attributed to the selection bv the 



