BOARD OF GAME AND FISH COMMISSIONERS 
63 
or scooping it up with their broad strainer bills has earned for them the name 
of “puddle ducks” among sportsmen. They are not overly fastidious in their 
tastes and will eat almost anything from a mosquito to a dragon fly, from a tad¬ 
pole to a crayfish or from a tiny duckweed to a hard-shelled hickory nut. The 
latter object, unbelievable as it seems, is easily ground to bits in the powerful 
gizzard of the larger species. The principal part of the diet consists, however, 
of vegetable matter derived from an immense variety of plants, chiefly aquatic. 
A bulletin, No. 720, recently issued by the United States Department of Agriculture, 
entitled the Food Habits of the Mallard Ducks of the Ufiited States, shows that 
about nine-tenths of the food of the common Mallard is derived from the vegetable 
kingdom. The remaining one-tenth consists chiefly of mollusks, insects, fish, and 
crustaceans in the order named. The amount of food consumed at a single meal 
is surprising. One Mallard’s stomach contained seeds as follows: bulrush 28,160, 
another sedge 8,700, primrose willow 35,840 and 2,560 duckweed a total of 75,200 
“as the principal items.” Another contained 102,400 seeds of the primrose willow, 
sufficient to sow two and and one-half acres of ground placing the seeds one foot 
apart each way. 
In addition to a considerable list of other injurious and objectionable insects 
the ducks of this group are credited with disposing of immense numbers of mos¬ 
quitoes by devouring the pupae and larvae of these much abhorred and, in some 
cases, disease-carrying little pests. The late Dr. Samuel G. Dixon, while Health 
Commissioner of Pennsylvania, published an article in the Journal of the American 
Medical Association for October 3, 1914, detailing results of experiments made by 
him along this line. Two dams were constructed on a stream so that the ponds 
would present exactly the same conditions. One was stocked with gold fish and in 
the other twenty Mallard Ducks were allowed to feed. After several months the 
duck pond was entirely free from mosquitos while the fish pond “was swarming 
with young insects in different cycles of life.” Ten well-fed Mallards were then 
admitted to the infested pond. At first they were attracted by the tadpoles but 
“soon recognized the presence of larvae and pupae of the mosquito and immediately 
turned their attention to these, ravenously devouring them in preference to any 
other food present. At the end of 24 hours no pupae were to be found and in 48 
hours only a few small larvae survived.” He adds “For some years I have 
been using ducks to keep down mosquitos in swamps that would have been very 
expensive to drain, but I never fully appreciated the high degree of efficiency of 
the duck as a destroyer of mosquito life until the foregoing test was made.” This 
is certainly very interesting and would seem to be worthy of further investigation. 
The Wood Duck, which was considered a few years ago to be rapidly ap¬ 
proaching extinction, is unquestionably increasing in numbers in Minnesota of late, 
as anyone who will visit the forest lakes of the northern portion of the state will 
readily believe. The cutting off of the forests and consequent destruction of its 
nesting places in cavities in trees, coupled with the primitive hunting skill that 
sufficed to bag it, were the chief factors that led to its specially rapid decrease. 
Where conditions permit this duck feeds extensively on acorns in the fall of the 
year, resorting for that purpose to open oak woods where it alights on the ground 
and gathers the fallen nuts. In days now long past the writer has s^en consider¬ 
able flocks of these birds thus engaged in oak groves now almost within the busi¬ 
ness portion of the city of Minneapolis. Mallard Ducks and perhaps other related 
species a Iso eat acorns at times in considerable quantities. 
