FOOD HABITS OF MALLARD DUCKS. 11 



from all other ducks. The black duck differs radically from the 

 mallard in coloration; however, and also is different from that species 

 in having the sexes colored alike. In temperament, furthermore, 

 the black duck varies considerably from its more abundant relative. 

 It is wilder, seldom lapsing from an attitude of intense wariness; it 

 appears keener in every way, and its senses of sight, hearing, and 

 smell are constantly alert. It is, therefore, a gamier species than the 

 mallard, and for the same reasons is not so susceptible to domestica- 

 tion. It is also distinctly more nocturnal in habit than the mallard. 



Vernacular names for the species, other than the one commonly 

 used, include dusky duck, black mallard, black stock duck, and 

 canard noir. 



Breeding from Virginia and Iowa north to Hudson Bay and Lab- 

 rador, the black duck ranges in winter from Nova Scotia south to 

 Florida and Louisiana, and casually to Colorado.^ It is not dis- 

 tributed uniformly over this region, however, and the probabilities 

 are that a large majority of the individuals winter in the Atlantic 

 Coast States from New England to the Carolinas. 



FOOD HABITS. 



Unevenness in distribution results in the black duck's feeding more 

 extensively than the mallard in salt marshes and other areas char- 

 acteristic of the coast region. In such places animal food, as mol- 

 lusks and crustaceans, is abundant and contributes more to the sub- 

 sistence of ducks than is the case in inland waters. Accordingly, the 

 black duck consumes almost three times as much animal food as the 

 mallard. The actual percentages, contrasted, are, respectively, 24.09 

 and 9.47. Due to its habit of frequenting salt water, the black duck 

 also devours far more eelgrass (Zostera marina) than the mallard. 

 The total percentage of vegetable food is 75.91. 



The number of black duck stomachs examined was 622, In tab- 

 ulating the results 232 stomachs were excluded, as they were either 

 nearly empty or were taken in poorly represented months. The 

 statements as to percentages of food, therefore, are based on the con- 

 tents of 390 stomachs collected in the six months from September to 

 February. This material was obtained in 19 States and in 2 Cana- 

 dian Provinces. The -distribution both geographically and through 

 the months is very satisfactory. 



Vegetable Food. 



Three-fourths (75.91 per cent) of the food of the black ducks ex- 

 amined consisted of vegetable matter, and fully half, of this was 

 derived from such submerged plants as the pondweeds, eelgrass, and 



1 Opinion is now almost unanimous that there are two forms of the black duck, a red-legged bird (Anas 

 rubripes rubripcs), occupying the whole northern and interior range of the species; and a dark-legged race 

 (A. r. tristis), occurring along the Atlantic coast up to the Gulf of St. Lawrence. 



