(almost all the species except the Shore Lark and its races), Pipits (Anthus), 

 certain European Warblers (Sylviince), various members of the Fringillidce, 

 and some of the shore and moorland haunting Limicolce, as the Curlews 

 (Numenius), and other Waders. Some of the more sedentary and local of 

 the migratory field birds, as for example, the North American Yellow-winged 

 Sparrow (Ammodramus savannarum passerinus) and the European Quail 

 (Coturnix communis), have developed more highly specialized patterns of a 

 very subtle nature, — patterns beautifully suggestive of the intricate small forms 

 of earth and grasses. But it is among the actually sedentary (i. e., non-migra- 

 tory) ground-birds of mountain moors and pastures, monotonous and little- 

 varied regions, where the forms of vegetable growth which cover the summer 

 ground are very limited in number, that the most simply specialized of back- 

 ground-pictures may be found. Such birds are the Ptarmigans (Lagopus), 

 already mentioned as preeminent among special-pattern birds. Living 

 always in exposed situations, and being much sought by many rapacious birds 

 and mammals, they are peculiarly dependent on protective coloration, at 

 all seasons. Almost all the species (the sole exception, as far as I know, 

 is the Scotch "Grouse," Lagopus scoticus) turn white in winter, when their 

 boreal or alpine haunts are covered deep in snow. In spring and fall the 

 birds pass through a long intermediate stage, when they are curiously and 

 ever-varyingly pied with white and brown or gray. The fact that they are 

 thereby aided to escape detection on brown vernal ground mottled with 

 patches of melting snow, or on ground half dimmed with scanty autumnal 

 snowfalls, might be considered nothing more than a coincidence, were it 

 not for the extraordinary slowness of the two seasonal color-changes. There 

 is perhaps no other bird which moults as gradually as the Ptarmigan, and this 

 fact goes very far to strengthen the supposition that it has developed a pecu- 

 liarly fluid and perfect system of perennial protective coloration. Figs. 

 8, 9, 10 and 39 show White-tailed Ptarmigans, of the Rocky Mountains, in 

 winter and transitional plumages. The photographs were taken from wild 

 birds in their native haunts. Supremely beautiful and potent is the grass- 



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