TADORNA. 519 



Genus TADORNA. 



The Sheldrakes were included in the genus Anas by both Linnaeus and 

 Brisson ; but in 1822 Flemings in his ' Philosophy of Zoology ' (ii. p. 260), 

 and Boie, in the 'Isis^ (1822, p. 56), made a new genus for the reception of 

 the Common Sheldrake, each of them adopting the specific name which 

 Linnaeus bestowed upon this bird (which consequently becomes the type) as 

 the title of the new genus. 



The Sheldrakes, being also non-diving Ducks, resemble the species of the 

 genus A?ias in having the hind toe furnished with a very small membrane. 

 They are large birds, with the tarsus nearly as long as the middle toe and 

 claw, and the colours of their plumage are generally black, white, and 

 chestnut. The shoulder of the wing is white and armed with a projecting 

 knob, like an incipient spur, but covered with feathers. 



The Sheldrakes resemble the Geese, not only in having longer legs than 

 the other Ducks and the Swans, but also in the important facts that the 

 difference between the sexes is generally very slight, and that the drake has 

 no summer dress. Both sexes moult once in the year, in autumn, the 

 drake a month earlier than the duck. 



Only six species of Sheldrakes are known : two breed in the temperate 

 portion of the Palaearctic Begion, one in South Africa, two in Australia, 

 and one in New Zealand. 



The flight of the Sheldrakes is very diflferent from that of the Ducks 

 and Geese, but closely resembles that of the Swans, being performed, like 

 that of most large birds, by slow and regular beats of the wings. They 

 swim with ease, but rarely dive. On the land they walk almost as well as 

 the Geese. They are almost exclusively coast-birds, being rarely found 

 inland except on salt lakes or saline marshes. It is difficult to say whether 

 they are fonder of animal or of vegetable food. Their notes are harsh. 

 They select holes under ground, the ledges of cliffs, or hollow trees in 

 which to lay their eggs. The Sheldrakes further resemble the Geese, and 

 differ from the Ducks, in the circumstance that the drake takes his share 

 in the education and protection of the young. 



