38 BULLETIN 862, U. S. DEPARTMENT OF AGRICULTURE. 



the seeds and other parts of submerged plants) by half-diving, 

 after the manner of the mallard and several other ducks. 



The stomachs of 413 13 wood ducks were available for examination. 

 Six stomachs were rejected on account of the too meager or uncertain 

 nature of their contents, and seven more from ducks collected during: 

 January, May, and June, because they were not sufficient in number 

 adequately to represent those months. None were taken during 

 July; so that the 399 stomachs from which final results were com- 

 puted represent only the months from August to December, and 

 from February to April, inclusive. There is no reason why the food 

 for January should not be similar to that of the other winter months; 

 in summer, however, the percentage of animal food no doubt is 

 somewhat higher. Stomachs were collected from 24 States and the 

 District of Columbia, from Maine and Florida to Oregon and Cali- 

 fornia, and from the Province of Ontario to Texas; but about five- 

 eighths (268) of the whole number were taken in Louisiana. The 

 bulk of the wood ducks, now nowhere abundant as breeders, inhabit 

 the Mississippi Valley, and in winter they find ideal feeding and 

 living conditions in the cypress swamps and wooded lakes and 

 lagoons of the States bordering the Mississippi from about the mouth 

 of the Ohio River southward. 



Vegetable Food. 



More than nine-tenths (90.19 per cent) of the food of the wood 

 duck consists of vegetable matter. This high proportion of vege- 

 table food is very similar to that taken by the mallard. With the 

 wood duck it is quite evenly distributed among a large number of 

 small items, chief among which are the following: Duckweeds, 10.35 

 per cent; cypress cones and galls, 9.25; sedge seeds and tubers, 9.14; 

 grasses and grass seeds, 8.17; pondweeds and their seeds, 6.53; 

 acorns and beechnuts, 6.28; seeds of waterlilies and leaves of water 

 shield, 5.95; seeds of water elm and its allies, 4.75; of smartweeds and 

 docks, 4.74; of coontail, 2.86; of arrow-arum and skunk cabbage, 

 2.42; of bur marigold and other composites, 2.38; of buttonbush 

 and allied plants, 2.25; of bur reed, 1.96; wild celery and frogbit, 

 1.31 ; nuts of bitter pecan, 0.91 ; grape seeds, 0.82; and seeds of swamp 

 privet and ash, 0.72 per cent. The remaining 9.4 per cent was made 

 up of a large number of minor items. 



DUCKWEEDS (LEMNACEAE), 10.35 PER CENT. 



Whenever present in the feeding grounds of the wood duck, duck- 

 weeds probably are its favorite food. Each individual plant con- 

 sists simply of a small fleshy leaf, disk shaped or nearly so, floating 

 on the surface of the water, with one or more simple roots dangling. 



u Eighty-six of these were examined by W. L. McAtee. 



