ANAS. 



527 



Genus ANAS. 



The genus A7ias of the ' Systema Naturae ■" of Linnaeus (twelfth edition^ 

 i. p. 194) contained the Swans and the Geese as well as the Ducks. 

 Brisson^ in his ' Ornithologia/ restricted it to the Ducks, but, contrary to 

 his usual custom^ did not designate a type, unless we regard his first and 

 fourth species^ which he calls Anas anas domestica and Anas anas f era, as 

 two forms of the typical species. Since Brisson-'s time no group of birds 

 has suffered more from the hands of the genus-makers_, who have literally 

 made " ducks and drakes " of it to such an extent that there are very few 

 species which have not been made the type of a parvenu genus by some 

 ornithologist or other in his anxiety to split it up. These pseudo-genera 

 may be all relegated to the waste-paper basket^ with the exception of 

 perhaps four or five, some of which can be admitted only on sufferance, to 

 prevent the suppression of long-familiar names. 



The restricted genus Anas will then consist of the well-defined group of 

 non-diving Ducks, with the exclusion of the Sheldrakes, which may fairly 

 be regarded as a very closely allied but distinct genus. 



The narrow membrane attached to the hind toe distinguishes the birds 

 in the genus Anas from all their allies except from the Sheldrakes. The 

 latter are so closely allied to the non-diving Ducks that I am unable to 

 find any external character to distinguish them beyond the prevalence of 

 chestnut in the colours of the plumage and the white shoulder. The tail 

 seems to be more rounded in the Ducks belonging to the genus Anas, the 

 tarsus to be slightly shorter, and their habits somewhat different. 



The flight of these Ducks is straight and very rapid ; they swim with 

 great ease, but rarely dive; and they walk somewhat clumsily. They 

 breed near inland waters or swamps, but are often seen on the mud-flats of 

 the coast in winter and on migration. They feed on both insects and 

 plants. Their notes are harsh. They breed on swamps and moors, 

 occasionally in an old nest in a tree, but never in holes in the ground. 



With one or two exceptions the males are much more brilliant in colour 

 than the females. These Ducks have only one complete moult in the 

 year, but the drakes of most species, though not of all, moult their small 

 feathers twice. As soon as the young are able to fly, the female moults 

 all her feathers, beginning with the small ones and concluding with those 

 of the wings and tail. The moulting of the male is quite different. As 

 soon as the female has begun to sit, the male in most species has a com- 

 plete moult, changing all his small feathers into an unobtrusive plumage. 



