of North American Wood Warblers (Mniotiltidce), are a few of the many ex- 

 amples among the smaller land birds. (See Figs. 58-61.) 



It might be supposed that a marking in such rank violation of the para- 

 mount ' obliterative ' principle as a jet-black breast or belly, with lighter 

 tones above it, could not fail to make a bird exceedingly conspicuous; but this 

 isby no means true. Such a marking, especially when it ends sharply against 

 a lighter tone, thence upward counter shaded, tends in aspect to detach itself 

 from the rest of the bird's dim body, and to unite with the background as a 

 hole or other very dark detail, thereby 'breaking up' its wearer's character- 

 istic form. This is the coloration for instance of the Black-bellied and Golden 

 Plovers (Charadrius and Squatarold) in summer plumage, and of the adult 

 male Massena Quail (Cyrtonyx montezumce and its subspecies) of Mexico, 

 etc. In the case of such birds as the male Eider Ducks, however, there is 

 virtually no counter shading above or below, — the obliterative scheme con- 

 sisting almost wholly of a series of 'breakages' achieved by sharply contrast- 

 ing patches. 



All these bolder schemes of pattern mask their wearer in a distant view 

 and in many views, whereas the delicate picture-patterns based on perfect ob- 

 literative shading play their full part only in a near view and against one par- 

 ticular type of background. In such a case, details of light-and-shade and 

 minor surface markings count for much. But give the object a greater dis- 

 tance from the beholder, and manifold vicissitudes of position and illumina- 

 tion, and it is contour that betrays it — contour, relieving with varying degrees 

 and kinds of conspicuousness against varying backgrounds. Combating 

 this principle, Nature has given many of her animals bold and brilliant 'rup- 

 tive ' patterns, which insure them, in lieu of elaborate and single background- 

 matching, the highest average of fragmentary background-matching, in many 

 situations and from many view-points. (See Plates V and VI.) 



79 



