OF THE BRITISH ISLANDS. 339 



Subfamily ANATIN/E, or Sheldrakes and 

 Non=diving Ducks. 



The birds included in the present subfamily are distinguished from their allies 

 by having the metatarsus scutellated in front, and only a narrow membrane attached 

 to the hind toe. The bill is rather flat and broad. None of the species contained 

 in this group ever dive for their food, which they search for on land or in shallow 

 water, only submerging the fore half of the body whilst probing and sifting the mud 

 and weeds for sustenance. In the Sheldrakes the sexes are nearly alike in colour, 

 but in the Ducks there is usually considerable sexual difference in this respect. 

 The Sheldrakes moult once in autumn, but the Non-diving Ducks have one com- 

 plete moult in autumn, and the males of many species moult their small feathers 

 twice once in early summer and once in autumn. 



This subfamily is composed of upwards of seventy species, divisible into about 

 a score fairly well-defined genera. 



