ative' function, on a wounded bird in hiding. The white specklings of some 

 of the Wood Sandpipers (Totanus) and various other water-haunting birds 

 (e. g., the loons, Gavia) belong more or less strictly to this same class of 

 'water-glint' pictures. 



So, too, the rails' barred flank-pattern has affinities with the markings of 

 other water birds, such as certain ducks. On them, however, it is developed 

 into ripple-picturing. The beautifully contrasted black-and-white bars on 

 the flanks of the Wood Duck (Aix sponsa) are ripple pictures, and as potent, 

 in their place, as the most elaborate markings of land birds — while they are 

 even more remarkable in that they depict motion. These markings of the Wood 

 Duck cross the flank feathers transversely, yet when the feathers are laid 

 in their natural upcurled position, overlapping the wing, their pattern forms 

 one brilliantly accentuated horizontal stripe. Thus, though made by flank 

 feathers, this marking is merely another form of the longitudinally striate 

 scapular- or wing-pattern worn by so many other ducks, and serves ex- 

 actly the same purpose. More than two thirds of the American and 

 European ducks have one form or another of this marking, and on many of 

 them it is most pronounced. It corresponds to the 'secant' stripe of certain 

 land birds, but is often more elaborate (consisting sometimes of several tiers 

 of stripes), and has an even more definite ' obliterative ' use. It may be seen 

 in its perfection on the Wood Duck, already mentioned, on the Pintail (Dafila 

 acuta), the Green- winged Teals (Nettion), the Garganey (Querquedula circia), 

 the Widgeons (Mareca), the Golden-eyes (Clangula clangula, etc.), the Long- 

 tailed Duck or Old Squaw (Harelda hyemalis), the Steller's Eider (Eniconetta 

 stelleri), the Hooded Merganser (Lophodytes cucullatus), and the Red-breasted 

 Merganser (Merganser senator). Its position varies from the flank feathers, 

 as in Aix, to the secondary wing feathers, as in Merganser, the tertiaries, as 

 in Mareca, and the scapulars, the feathers of the sides of the back, as in Dafila, 

 Nettion, Harelda — in fact, the great majority of species. Its character and 

 effect, however, are nearly the same in these several positions. A swimming 

 duck leaves a spreading, wedge-shaped trail of curling ripples, very noticeable 



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