INTRODUCTION. 11 



hand, and as an impermeable oar on the other, when situated in the 

 wing, and required to catch and retain the impulse of the air. In 

 the birds which do not fly, and inhabit warm climates, the feathers 

 are few and thin, and their lateral webs are usually separate, as in the 

 Ostrich, Cassowary, Emu, and extinct Dodo. In some cases 

 feathers seem to pass into the hairs, which ordinarily clothe the 

 quadrupeds, as in the Cassowary, and others ; and the base of the 

 bill in many birds is usually surrounded with these capillary plumes. 

 The greater number of birds cast their feathers annually, and 

 appear to suffer much more from it than the quadrupeds do from a 

 similar change. The best fed fowl ceases at this time to lay. The 

 season of moulting is generally the end of summer or autumn, and 

 their feathers are not completely restored till the spring. The male 

 sometimes undergoes, as we have already remarked, an additional 

 moult towards the close of summer ; and among many of the waders 

 and web-footed tribes, as Sandpipers, Plovers, and Gulls, both sexes 

 experience a moult twice in the year, so that their summer and 

 winter livery appears wholly dilferent. 



The stratagems and contrivances instinctively employed by birds for 

 theii support and protection, are peculiarly remarkable ; in tliis way 

 those which are weak are enabled to elude the pursuit of the strong 

 and rapacious. Some are even screened from the attacks of their 

 enemies by an arrangement of colors assimilated to the places which 

 they most frequent for subsistence and repose : thus the Wryneck 

 is scarcely to be distinguished from the tiee on which it seeks its 

 food ; or the Snipe from the soft and springy ground which it fre- 

 quents. The Great Plover finds its chief security in stony places, 

 to which its colors are so nicely adapted, that the most exact observer 

 may be deceived. The same resort is taken advantage of by the 

 Night-Hawk, Partridge, Plover, and the American Quail, the young 

 brood of which squat on the ground, instinctively conscious of being 

 nearly invisible, from their close resemblance to the broken ground 

 on which they lie, and trust to this natural concealment. The same 

 kind of deceptive and protecting artifice is often employed by birds 

 to conceal, or render the external appearance of their nests ambigu- 

 ous. Thus the European Wren forms its nest externally of hay, if 

 against a hay-rick ; covered with lichens, if the tree chosen is so 

 clad; or made of green moss, when the decayed trunk in which it 

 is built, is thus covered ; and then, wholly closing it above, leaves 

 only a concealed entry in the side. Our Humming-bird, by external 



