CHAPTER VII 



BACKGROUND-PICTURING ON COUNTER-SHADED BIRDS, CONTINUED. GRASS 

 AND HEATHER PATTERNS ON SPARROWS AND GALLINACEOUS BIRDS, ETC. 



rx^HE grass-pattern birds, of various orders, constitute a pretty clearly- 



A defined group in the obliteratively-patterned series. Generally speak- 

 ing, there is much less diversity in the backgrounds of terrestrial birds which 

 live in the open, than in those of forest birds, whether terrestrial or arboreal. 

 The ingredients of a field bird's background are comparatively few and 

 simple, for the predominant vegetable forms of the open land are much less 

 diverse in size, and somewhat less in shape, than those of the forest. Further- 

 more, birds that are habitual dwellers on open ground — which, relatively to. 

 the littered forest floor, lacks minor variations of level — are rarely seen against 

 anything but a very near background. Thus the possibility of their needing 

 the distance-picturing type of obliterative pattern (as described at the be- 

 ginning of Chapter VI) is largely eliminated. This comparative simplicity 

 of marking requirements would lead us to expect great uniformity in the 

 patterns of field birds; and investigation vindicates the supposition. Among 

 the birds which are wholly confined to open ground, either bare or grass- 

 grown, but which annually range over a wide territory, so that no one region's 

 peculiar ground-forms could advantageously be pictured on them, there 

 exists a highly conventionalized ground-pattern of a fixed type, which is re- 

 markably little varied through several genera and families, even orders. 

 This type, always based on complete obliterative shading, is characterized 

 by striations of light brown and black, coarsest on the back, and more or 

 less varied by transverse bands and finer markings on the wings, scapular 

 feathers, and other portions. Birds which wear it are Larks (Alaudidce) 



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