BANNER MARKS 95 



value of any color scheme or pattern of marking is active only when 

 the animal bearing it is at rest. Without re'gard to color, movement at 

 once reveals, and bearing this in mind, the action of a bird in the pres- 

 ence of danger is a supreme test of the protective or non-protejctive 

 value of its colors. 



If the bird is wary and can be approached only with difficulty, 

 we may feel assured that it realizes its conspicuousness and conse- 

 quently it relies for safety on its watchfulness and its wings. But if 

 the bird attempts to hide and flies only when convinced that it has been 

 discovered, then we may believe that it relies primarily on the nature 

 of its coloring to escape observation, when we are evidently justified 

 in assuming that its colors are truly protective. Compare the colors 

 and actions of such 'wild' birds as Gulls, Terns, Skimmers, Ducks, 

 Geese, Cormorants, Cranes, Herons, Flamingoes, Stilts, Avocets, and 

 Crows, with those of birds which take wing only to avoid being stepped 

 on (e. g. Bitterns, Rails, Woodcock, Wilson Snipe, Quails, Grouse, Whip- 

 poor-wills) to appreciate how closely color is here correlated with habit. 



Compare further the colors and habits of the flightless young of Gulls, 

 Terns, Skimmers, Stilts or Avocets with those of their parents to observe 

 how there may be both a protective and a conspicuous plumage in the 

 same species. Enter the breeding resorts of any of these birds and the 

 conspicuously colored adults at once take wing while the protectively 

 colored young, squatting motionless, make no attempt to escape, even 

 by running, until they are actually touched. 



Obviously, then, the significance of the colors of birds is to be learned 

 only by the study of species by species in nature. The whole subject 

 is preeminently within the domain of the field naturalist. Only when 

 our knowledge of a bird's haunts and habits, its food and foes, and its 

 actions in the presence of danger is reasonably complete are we in a 

 position to determine to what factors we may attribute its particular 

 colors and markings. This is the ground taken by Theodore Roosevelt 

 in his extended criticism ('11) of Abbott Thayer's theories, and while 

 one may argue that Mr. Roosevelt underrates the necessity of conceal- 

 ing coloration in animals, one must commend his admirable plea for the 

 accumulation of further evidence from nature before giving a verdict. 



Banner Marks. The plumage of many birds contains marks which 

 are usually conspicuous only when the bird is in motion. White outer 

 tail-feathers (e. g. Junco, Vesper Sparrow, Meadowlark), or wing- 

 patches (e. g. Mockingbird), or a white rump (e. g. Flicker), are mark- 

 ings of this type and to them the term 'banner', 'recognition' or 

 'directive' marks have been applied. 



Some authors would have us believe that such flight-revealed mark- 

 ings have a directive value which assists birds of the same species in 

 keeping together (see Tracy, '10) but the ease with which dull-eyed man 

 learns to recognize birds, even at a great distance, makes it difficult 

 to believe that birds require some conspicuous mark to distinguish 

 others of their own kind, as Abbott Thayer has well shown (The Auk, 



