maculata), stick to grassy swamps throughout the year, and their pattern 

 tells the tale. 



The true snipes (Gallinago), already treated of in another division because 

 of the rich intricacy of their markings, have a pronounced element of grass- 

 pattern, and both in markings and in habits form a connecting link between 

 the grass birds and the woodland bog birds, typified by the American Wood- 

 cock (Philohela minor). In like manner the sand- and pebble-type of pattern 

 is modified toward rock-surface picturing, — as in the winter plumage of the 

 Purple Sandpiper (Tringa maritima), one of the most highly 'obliterated' 

 of birds, and a sandpiper peculiar in its restriction (at least in winter) to rock- 

 bound ocean shores. In the same way the pattern of the terrestrial goat- 

 suckers, described in Chapter V, is modified toward rock-picturing in the 

 plumage of that rock-haunting member of the family, the Nighthawk (Chor- 

 deiles). 



From all this it appears that the types and forms of picture-pattern worn 

 by birds, though easily separable into classes when grouped about the several 

 conspicuously pure examples, are yet in the whole range of species closely 

 blended and intermingled, more or less irrespective of the structural affinities 

 of the birds which wear them, but nearly always in obvious conformity with 

 their specific habits. It would seem, indeed, as if Nature in its entirety 

 should represent one great, blended scale, shaded throughout insensibly like 

 the colors in the spectrum, and as if the breaks and interruptions which form 

 the bases of zoological classification and separate grouping were in a sense 

 imperfections. In the world of birds, for instance, though the breaks and 

 anomalies are numerous, there are yet many evidences of the past existence of 

 a smooth gradation connecting types now sundered.* On the other hand, it 

 is also true that gaps in the fundamental affinities of birds are often super- 

 ficially bridged over by similar habits, probably of more recent acquirement, 

 and these are usually accompanied by corresponding outward resemblances, 



* See Robert Ridgeway, in the preface to his " Birds of North America," whence much of this 

 thought is taken. 



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