. Key to North American birds. Containing a concise account of every species of living and fossil bird at present known from the continent north of the Mexican and United States boundary, inclusive of Greenland and lower California, with which are incorporated General ornithology, an outline of the structure and classification of birds, and Field ornithology, a manual of collecting, preparing, and preserving birds . relativelyshorter tarsi, longer toes (outerscarcely or not shorter than mid-dle), and broader webs; they arealso placed somewhat farther back,in consequence of w^iich the gait isst
. Key to North American birds. Containing a concise account of every species of living and fossil bird at present known from the continent north of the Mexican and United States boundary, inclusive of Greenland and lower California, with which are incorporated General ornithology, an outline of the structure and classification of birds, and Field ornithology, a manual of collecting, preparing, and preserving birds . relativelyshorter tarsi, longer toes (outerscarcely or not shorter than mid-dle), and broader webs; they arealso placed somewhat farther back,in consequence of w^iich the gait isstill more awkward and constrained than the waddle of ordinary Ducks; but swimmingpowers are enhanced, and diving is facilitated. A large number of the species are exclusivelymaritime, but this is no more the case with all of them than is the reverse with the RiverDucks. These birds feed more upon mollusks and other animal substances (not, however,upon fish, like Mergansers) than River Ducks do, and their flesh, as a rule, is coarser, if notentirely too rank to be eaten ; there are, however, signal exceptions to this, as in the case ofthe Canvas-back. The sexes are unlike, as among Anatince; and besides the difference in■color, the 9 is often distinguished by absence or slight development of certain tuberosities ofbill that the ^ of several species, as of Scoters and Eiders, possesses. The tracheal tympanum. Flo. 643. — Canvas-backXewis.) Red-head. (From — : SEA DUCKS. 921 is present in FHlignlince, as a rule, and differs from its ordinary type in Anatince by greaterirregularity of figure as well as by the imperfection of its solid walls, which may present sev-eral fenestra} or vacuities closed up only by membrane. A large majority of the species in-habit the Northern Hemisphere; there are rather more than 50 in all, exhibiting a good dealof diversity in minor details, and thus requiring recognition of many genera, most of \vhich arewell represented in N
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectbirdsnorthamerica
