CAROLINA DUCK 57 



is uttered as a warning call. Heinroth describes the note the female utters during 

 flight when calling to companions on the pond below as very peculiar and resembling 

 the syllable hudk. There are also other modifications of the hoe-eelc call. Another 

 quite distinct note is heard during autumn and winter, a certain krui or kerri, which 

 is thought to express a coquettish mood. A very different note is heard from the 

 female when nest-hunting in spring, — a soft and very continuous te-te-te-te, and by 

 this murmuring note one can determine the beginning of the season of sexual activ- 

 ity. Heinroth says it is also used in what he calls the "engagement game," in order 

 to arouse the male. Those who have been fortunate enough to observe the female 

 calling or coaxing the young to drop down from the nest-hole have described the 

 sound as like kuck, kuck, Jcuck, Icuclc, kuck, rapidly repeated from five to twelve 

 times. While watching feeding wild male birds in the autumn at very close ranges, 

 I have heard a very low squeaking jeeb with an occasional drum-like quality to it, 

 kept up for a long time. This was certainly not audible at more than eight or ten 

 yards. 



The downy young peep like the ducklings of other species, but not so loudly as 

 young Mallards; in the Carolina Duck the note is usually uttered twice in succes- 

 sion. Even after the young are on the wing there may still be doubt as to their sex, 

 judging from the voice alone, for the hoe-eek of the female is still so fine and acute as 

 to be easily confounded with the jiib of the adult male. The notes of the Mandarin 

 are similar in character but have a different tone. 



The trachea of the male (figured by Eyton in 1838) is not very different from that 

 of many other species. The bony box at the bifurcation is left-sided, very thin-walled, 

 and nearly two centimeters in its longest diameter (see under general account). 



Food. The Carolina Duck is an omnivorous species, feeding chiefly, according 

 to Audubon, on beechnuts, acorns, and berries of various sorts, besides insects, 

 snails, tadpoles, and small water-newts. In the Carolinas he found them feeding in 

 the rice-fields as soon as the grain became milky. Howell (1911), speaking of Ar- 

 kansas, lists the seeds and leaves of aquatic plants (such as the water-lily, pond- 

 weed, and wild rice), acorns, beechnuts, chestnuts, wild fruits, and insects. McAtee 

 (1911) in an analysis of seventy-five stomachs found wild rice 11.62, wild celery 3.17, 

 pond-weed 6.72, or a total of 21.51% for these three foods alone. McAtee (1915) 

 mentions swamp-privet as a very important food, on the testimony of numerous 

 hunters. The birds are said to consume the seeds, leaving little for other species of 

 ducks when they arrive. In California the species has been found feeding in corn- 

 and wheat-fields after harvest, and consuming also wild grapes and acorns, this lat- 

 ter appearing to be a very general article in the diet of western birds (Grinnell, 

 Bryant, and Storer, 1918; J. Dixon, 1924). The elongated fruits of the valley oak 

 sometimes reach a length of %\ inches, but they are not too big for a hungry Caro- 



