2 BULLETIN 720, U. S. DEPARTMENT OF AGRICULTURE. 
our most valuable game ducks and includes the most important single 
species—the common mallard (Anas platyrhyncha). The others are 
the dusky or black duck (Anas rubripes) and the southern black duck 
(Anas fulvigula). 
These river ducks rarely dive so as to disappear entirely beneath 
the water, but obtain their food in shallows by dipping the head and 
neck or by submerging all of the body but the tipped-up tail. Vigor- 
ous paddling with the feet is needed to maintain the latter position 
in the water. The food usually is obtained within 12 to 16 inches of 
the surface, and as a result river ducks obtain fewer of the under- 
ground organs of aquatic plants than the diving ducks. These root 
systems of the plants include the rootstocks, stolons, tubers, and 
winter buds, which are stocked richly with nutriment. However, 
the river ducks wax fat by their own way of living, and although they 
are distinctly successful foragers, expediency seems to be their rule, 
as they are more nearly omnivorous than any other ducks. 
MALLARD. 
(Anas platyrhyncha.) 
The mallard (see frontispiece) probably is the most abundant wild 
duck in the world, and its range covers the entire northern portion 
of the earth. Wherever it occurs it is popular and is usually the 
favorite waterfowl. Various races have claimed it for their own, and 
in consequence it has received such names as English duck and canard 
francais (French duck). Other common names are wild duck, green- 
head, gray mallard, and stock duck. The last name refers to the 
fact that the mallard is the source of most of the breeds of domesti- 
cated ducks. That it is possible under controlled conditions to pro- 
duce mallards typically wild both in appearance and behavior has 
been taken advantage of on duck farms, where birds are reared both 
for market and sport. 
The ease with which the mallard can be bred makes it the best 
species for wild-duck farming. This is an industry which should be 
developed as extensively as possible, in order to supplement the de- 
creasing natural supply of game. ‘The mallard is not only susceptible 
of great increase by game farming, but also may very easily be assisted 
to increase in the wild state. Its breeding range is so extensive that, 
at least in the northern half of the United States, where local con- 
ditions are suitable, strict protection throughout the spring almost 
certainly will induce it to nest. 
Its beauty and popularity, hardiness, adaptability, and fecundity fit 
the mallard as no other duck is fitted to be the game duck of the 
future. Upon it should be centered a large share of the interest in 
duck farming and wild-fowl protection. Whatever is learned about 
