26 
ANAS BOSCH AS 
quacking note, corresponding to the clucking of the hen is also heard. Other and 
more complicated language is used when the female is “hounding on” the male, at 
which time, with a peculiar head-and-bill movement, she scolds away over her 
shoulder with a queggeggegegqueggegeg. This “clucking” note seems to be used in 
other ways, for instance in expectation of food, and it is sometimes heard when the 
bird is on the wing. At night one hears from a feeding flock long-drawn calls from 
the female, very high pitched for the first few syllables, and gradually decreasing in 
tone until they become inaudible amidst the noise made by the “dibbling” birds. 
The male note has much less variety, but during excitement the notes are shortened 
and run together. According to Heinroth the drake’s note may also be varied into a 
note of attraction used when the pair are searching for a nesting site, though I must 
confess that I have never distinguished anything of the sort. The drake does, how- 
ever, have an entirely different call, a short high-pitched w’histle, audible only for 
a short distance; it is used during the breeding season and particularly after the 
mating act. Other low notes are heard during the display. 
The peculiar bony enlargement of the trachea in males w'as described by Latham 
and Romsey in 1798, and by many writers since that time. It is large, left-sided, and 
connects directly with the left bronchus, probably affecting the voice by diverting the 
column of air. This tracheal bulb is already indicated in embryos ten days old, and 
in both sexes. But in females it begins to retrogress after the twenty-seventh day, 
till finally it disappears (Gadow, 1890). The downy young “peep,” as in all true 
ducks, and later on utter a note which is something between a quack and the drake’s 
note. The females are able to quack, though in a coarse rudimentary way, soon 
after the first plumage is assumed. But usually one can tell sex sooner by the color 
of the bill and plumage than by the sound of the voice. 
Food. Almost all sorts of aquatic plants, every kind of grain, beech-nuts, acorns 
and other upland foods have been found in the crops of Mallards. The birds are so 
omnivorous that though chiefly vegetable feeders, all kinds of aquatic animals are 
also eaten. Some of the more unusual “finds” will be mentioned below. For the nor- 
mal diet by far the best study is that by McAtee (1918), but even this is chiefly con- 
cerned with the winter food, and his specimens were drawn largely from the southern 
States of the Union, Louisiana being much more heavily represented than any other 
State. This analysis is based on 1725 gizzards, many of them accompanied by w'ell- 
filled gullets. It shows that the Mallard is a vegetable feeder, for 90.5% of the 
entire contents consisted of plant food, but the summer food of course contains a 
much higher proportion of animal matter. Different families of plants were repre- 
sented as follows: sedges, 21.62%; grasses, 13.39%; smartweeds, 9.83%; pondweeds, 
8.23%; duckweeds, 6.01%; coontails, 5.97%; wild celery and its allies, 4.26%; 
water elm and hackberries, 4.11%; wapato (duck potato) and its allies, 3.54%; 
