bark- and vista-pictures much like those worn by goatsuckers, as in the Wry- 

 necks. 



The unmarked Wood Creepers — ^whose counter shading also, in some 

 cases, is very slight — ^frequent brown stumps and trunks, in very heavily 

 shaded forests. Other members of the same family, with closely similar 

 habits, have streaks and a more pronounced counter shading. 



Bark picturing plays a very large part in the disguises of several classes 

 of animals, probably reaching its consummation among moths and butter- 

 flies, as we shall see later on. Cruder * forms of it among birds are represented 

 by the streakings and mottlings of the Creepers (Certhiidce and Dendrocolap- 

 tidoE), by the close transverse barrings of the backs of certain Woodpeckers, 

 and the bold spottings and stripings of other members of that family. AH 

 these devices, especially the barrings and stripings, are, at a little distance, 

 effective bark-pictures. The pattern of the small Northern Creepers {Cer- 

 thia) is perhaps too highly developed to be rightly classed among these others, 

 and should be treated rather as a connecting link between them and the ex- 

 quisite picture-pattern of the Common Wryneck (Jynx torquilla). This last 

 is one of the mpst wonderfully equipped and beautiful among obliteratively- 

 colored birds, and is evidently one which, like the goatsuckers, often stays 

 stock-still in time of danger, allowing its enemy to make an exceedingly near 

 approach before it moves. Its buff-colored breast and rufous primaries bear 

 the same form of transverse dusky barring as is worn by so many of the larger 

 forest birds, while its back is mottled and lined and peppered with several 

 tones of gray and dusky, in minute picturing of bark seen at close range. In 

 back view the bird would usually be seen against the very tree to which it is 

 clinging, in side view usually against branches and trunks, and more distant 

 forest vistas. And behold! its markings are developed correspondingly. 



* Whenever we call a coloration cruder, or less developed, without trying to state the function 

 of this so-called crudeness, it must be understood that such a function surely exists. It is, evidently, 

 only the need of this coloration to represent different backgrounds, that can limit its development 

 toward any particular one. — A. H. T. 



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