MALLARD 
37 
(1912) heard that five thousand Mallards and Black Ducks were brought into the 
market of Georgetown, South Carolina, in a single day. The markets of San Fran- 
cisco received 47,565 Mallards during the winter of 1895-96 (Grinnell, Bryant and 
Storer, 1918). In California the Mallard is said by these writers to have been re- 
duced in numbers, but not as much as the Red-head or the Carolina Duck. Irriga- 
tion has very much altered the breeding areas in that State, but fortunately, the 
effect is not proving as disastrous as was at first feared, although it has greatly 
changed the face of the country. According to the report of the Minnesota State 
Game Commissioner nearly half a million Mallards were shot in that State in 1919 
and 387,000 in 1920 but I feel certain that these figures are too high. 
A condition knowm as the “duck sickness” appeared in our own West some 
twenty years ago. In the Great Salt Lake region it began to be serious in 1910 and 
caused the death of hundreds of thousands of ducks in the following five years, so 
that a great decrease was noticed. This sickness has been definitely proved to be 
caused by the toxic action of certain salts found in alkali, the result of irrigation 
systems (Wetmore, 1918). 
The recovery by shooting of banded Mallards is a valuable record of the toll which 
man takes. In England there were 22% of recoveries (Witherby, 1922a) and in the 
United States the proportion is not very different. Of course not all these were 
taken the same year they were marked, but by far the largest proportion were. 
Enemies. Very few studies of the enemies of the Mallard have been made in 
America since the time of Audubon. That great authority mentions turtles and fish 
as being destructive to the young, and White-headed Eagles, Snowy and Virginia 
Owls, racoons, lynxes and snapping turtles as enemies of the mature birds. He was 
perhaps in error in ascribing much destruction to the White-headed Eagle, for that 
bird is chiefly a carrion feeder and turns his attention mostly to cripples, yet I am 
told that on the North Pacific coast he is very destructive to diving ducks and takes 
some Mallards, Pintails and Widgeons. The Duck Hawk {Falco peregrinus) is de- 
structive to ducks, and the Prairie Falcon {Falco mexicanus) has been mentioned as 
an enemy (Cameron, 1907). Crows, however, are much more serious than all these 
put together as they are persistent egg robbers and are increasing in many regions. 
Doubtless mink, weasels, wild-cats and prairie wolves account for some destruction, 
but the extent of this has never been estimated. The bull snake of the western States 
is fond of birds’ eggs and is known to swallow ducks’ eggs. 
Many English writers speak of the damage done to the young and half-grown 
Mallards by large pike. Payne-Gallwey (1882) mentions a pond where the old birds 
would not lead their young to the water until they were half-grown, because of the 
danger from these fish. Gulls {Larus fuscus) are described as very destructive to 
young Vlallards in northwestern Scotland (Harvie-Brown and MacPherson, 1904). 
