shed their quill-feathers all at once, and become absolutely incapable of 

 flight for a season, during which they generally seek the shelter of thick aquatic 

 herbage, and it is further to be particularly remarked that the males of two 

 sections of the family {Anatina and FuligulincB) at the same time lose the 

 brilliantly-colored plumage which commonly distinguishes them, and 'go into 

 eclipse,' as Waterton happily said, putting on for several weeks a dingy 

 garb much resembling that of th^ other sex, to resume their gay attire only 

 when, their new quills being grown, it can be safely flaunted in the open air." 

 Here are the facts, but without the true conclusion which' should be drawn 

 from ttem — ^the conclusion which is unavoidable in the light of a wider 

 knowledge of protective coloration. This is, that the male duck's assumption 

 of dull plumage is an adaptation to his new environment, rather than to his 

 altered bodily condition. He skulks among the reeds because he is flightless, 

 and he assumes a mottled grass- and reed-like pattern to fit him to this new 

 environment; but the mottled pattern is no more protective, i. e., 'obliterative,' 

 than the pied wa/er-pattern of his full plumage, worn when he forsakes the 

 shelter of the shore. Male Eiders (Somateria) keep out at sea while their 

 brown, mottled females (see Fig. 47) hatch the eggs (sometimes a long way 

 from the water) and tend the young, and though the males (as well as the 

 females) are flightless for a while, they retain their full plumage almost un- 

 altered. This full plumage has no obliterative shade-gradation, but con- 

 sists of a bold 'ruptive' pattern of ice- and water-colors— as will be further 

 explained in a later chapter. A few male sea-ducks, such as the more or 

 less wholly black Scoters (Oidemia), are conspicuous at sea, though well 

 equipped for inconspicuousness against dark cliffs. Their females, which 

 have to brood the eggs on shore, are more or less adequately ' obliterated ' 

 by counter shading, color, and markings. There are, however, some species 

 of swimming birds in which even the females are quite without counter 

 shading. Such are swans,* for instance, and cormorants — though cormo- 

 rants are otherwise equipped for concealment on shore by rock-like 



* See p. 154, Chapter XXII. 

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