94 COLOR AND CONCEALMENT 



prey or by their 'enemies. Or, as Gerald Thayer puts it: the object's 

 "oblitepatively-shaded surface must bear a picture of such background 

 as would be seen through it, if it were transparent." (1. c. p. 31.) Thus 

 our Woodcock is said to bear a picture of "dead leaves, twigs and 

 grasses, variously disposed over shadow-holes," while the plumage of 

 Wilson's Snipe represents "sticks, grasses, etc., with their shadows at 

 various distances." The plumage of the Upland Plover shows a "grass" 

 pattern, a type common to many field or upland species. Certain of 

 the Plover and Sandpipers wear this plumage during the summer, when 

 they live among weeds and grasses, but lose it for one of pure and 

 simple counter-shading when they winter along the shores and beaches. 



From these more obvious instances of obliterative picture patterns, 

 Thayer leads us to an interpretation of the brilliantly colored and in- 

 tricately marked plumage of birds like the male Wood Duck, Peacock, 

 and Paradise Bird (Paradisea), or of such special markings and appen- 

 dages as the speculum in Ducks, gorget in Hummingbirds, tail-coverts 

 in the Resplendent Trogon, etc., all of which, under certain vital con- 

 ditions, are considered by him to make or to aid in making their wearers 

 inconspicuous. The use of no pattern, mark or appendage is left un- 

 explained by the proposer of this law, and while naturalists recognidte 

 the importance of his studies, Thayer's contention "that patterns and 

 utmost contrasts of color (not to speak of appendages) of animals make 

 wholly for their 'obliteration,' " finds few supporters. 



Flamingoes, Crows, Ravens and Turkey Vultures, for example, 

 are seemingly from any point of view conspicuous. The nature of their 

 food and their excessive wariness or absence of foes apparently re- 

 move them from the action of the laws producing a true concealing 

 coloration. 



Protected primarily by the character of their haunts, it is not 

 improbable that the striking and endlessly varied colors of Tanagers, 

 Honey Creepers, Cotingas, Toucans, Trogons, Parrots and other bril- 

 liantly marked arboreal birds may be explained in a similar manner. 

 It is important to remember in this connection that many birds of such 

 habits are dull as well as brightly colored, and we may suggest that 

 among tree-haunting, and to a less extent thicket-haunting birds, the 

 actual physical causes of color, uncontrolled by natural selection, have 

 run riot. When, however, the nature of a bird's haunts affords it less 

 adequate means of concealment, then color plays a more important 

 part in protecting it, and there is consequently less variation from the 

 type of color which presumably has proved to have the highest conceal- 

 ing value. 



Thrushes, Ovenbirds and Doves, for example, which feed on the 

 ground, may frequent the tree-tops without unduly exposing themselves 

 to danger, but let a male Scarlet Tanager or other brightly-colored 

 arboreal bird alight upon the ground and, even when motionless, it 

 is conspicuous. 



This illustration may serve also to remind us that the protective 



