Shelldrakes 185 



and often causing considerable damage. Of its nest he says : "They breed in the 

 hollows of large trees, and lay from twelve to fifteen eggs ; the young are lowered 

 to the ground one at a time in the mouth of the mother; after all are safely landed 

 she cautiously leads her young brood to the nearest water. When taken young, 

 or the eggs hatched under the common barnyard hen, they become very domestic 

 without being confined; they are very watchful during the night, and, like the 

 Goose, give the alarm by their shrill whistle when any strange animal or person 

 comes about the house." The Indian Tree-Duck (D. javanica) has been ob- 

 served by Hume carrying its young in the claws, while others record their carry- 

 ing them on the back. 



Shelldrakes. As offering another step in the transition between the Geese 

 and Ducks, and making any sharp line between them impossible, we come to the 

 Shelldrakes (Tadorna), of which two species are known. They are large, strik- 

 ingly handsome birds, natives of the Old World, with rather long legs in which the 

 tarsus is covered in front with transverse scutes, thus conforming in this "Duck- 

 like " character to the true Ducks. They agree with the Geese, however, in the 

 plumage of the sexes being similar, and the male retaining the same dress through- 

 out the year. They agree with the Tree-Ducks in having a narrow membrane 

 connecting the toes, and in the single annual moult. The best-known and most 

 widely distributed is the Common Shelldrake (T. tadorna}, which spends the 

 summer from Europe to southern Siberia and Japan, and the winter in Africa, 

 India, and China. It is about twenty-six inches long and has the upper back 

 chestnut, the lower back, rump, upper tail-coverts, and tail white, the latter black- 

 tipped, the scapulars, a part of the secondaries and the primaries black, the wing- 

 coverts white, the head and upper neck glossy green, followed by a broad white 

 collar, while the lower parts are dark brown and black. The bill is provided with 

 a prominent knob, which, together with the bill itself, is bright red. It inhabits 

 the sandy seacoast, feeding on mollusks and marine insects. Curiously enough 

 they nest in burrows, sometimes excavating them for themselves, but oftener 

 making use of the abandoned holes of rabbits and foxes. The burrow is from 

 six to twelve feet long and ends in a chamber, which is lined with dry grasses, 

 moss, and quantities of down plucked by the female from her own body. The 

 eggs are from seven to twelve, creamy white in color. The other species (T. 

 radjati) is smaller, is without the knob on the bill, and has the whole head and 

 neck white. It occurs in New Guinea and Australia, and, according to Gould, 

 makes its nest in hollow trees. 



Shell-Ducks. Closely allied to the last, and by some included with them, 

 are the Shell-Ducks (Casarcd), of which four species are known, these being 

 widely distributed over the southern parts of the Old World. They are sepa- 

 rated mainly on the ground of the dissimilarity of the sexes. 



The Mallard (Anas boscas) may very appropriately be selected as a typical 

 representative of the true Ducks, for it is not only a very handsome bird, well 

 known throughout most of North America, but is equally well known and es- 

 teemed over temperate Europe and Asia. It is a large bird about twenty-four 

 inches long, with the head and neck a soft, brilliant metallic green, the chest a 



