of North American Wood Warblers {Mniotiltida), 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 beUy, with lighter 

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

 is by 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 Squatarola) 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 



