FOOD HABITS OP MALLARD DUCKS. 5 



For instance, Kumlien and Hollister' state that large numbers 

 of mallards wintering on the prairies of Wisconsin feed chiefly 

 in the cornfields. In Manitoba^ they are said to feed in wheat 

 and barley stubble, rapidly becoming fat. It has been said that 

 mallards at times are destructive to sprouting grain, but this is 

 hardly ti-ue. Even if mallards did feed extensively upon sprouting . 

 grain, little if any harm would result, as they would only nip off 

 the leaves, not dig up the grain. 



SMARTWEEDS (9.83 PER CENT). 



The seeds of smartweeds are produced abundantly in wet situa- 

 tions. Well fi:lled with nutritious material, it is no wonder they are 

 a favorite with wild ducks. The seeds of 13 species of smartweeds 

 have been identified from stomachs of the mallard, besides buck- 

 wheat, BrunnicMa, and dock, which belong to the same family. A 

 mallard collected at a locality where buckwheat was used for bait 

 had about 750 of the large akenes in its crop and gizzard. A smart- 

 weed with a prickly four-angled stem and arrow-shaped leaves (Po- 

 lygonum sagittatum) is a favorite with mallards. Its seeds were 

 identified in 107 stomachs, as many as 2,000 being found in one. 

 No fewer than 4,500 seeds of the water pepper (Polygonum Jiydropiper) 

 were taken from the crop and gizzard of another mallard. 



PONDWEEDS (8.23 PER CENt). 



The pondweed family is important to almost all ducks. These 

 submerged plants are abundant and widespread, usually produce a 

 good crop of seeds, and often have fleshy rootstocks and foliage 

 which are wholly edible. Seeds of pondweeds, not further identified, 

 were found in 431 mallard stomachs, up to 560 in number in a 

 single instance. Kemains of six species of the genus Potamogeton 

 were found during the analyses. The most important species for 

 the mallard as well as for other ducks is the sago pondweed (Pota- 

 mogeton pedinatus), of which stems, foliage, seeds, rootstocks, and 

 tubers all were eaten. Among other plants of this family, widgeon- 

 grass (Ruppia maritima) was found in 72 gizzards and bushy pond- 

 weed (Naias Jlexilis) in 67. No fewer than 5,500 seeds of eelgrass 

 (Zostera marina), a salt-water representative of the family, were 

 found in a single mallard's stomach. 



DUCKWEEDS (6.01 PER CENT) AND COONTAIL (5.97 PER CENT). 



Duckweeds (Lemnacese) thickly cover the surface of the water in 

 southern swamps,, and eoontail (Ceratophyllum demersum) fills the 

 water beneath. Both contribute materially to the subsistence of 



1 Bull. Wisconsin Nat. Hist. Soc, III, Nos. 1-.3, p. 17, 1903. 



2 Proc. U. S. Nat. Mus., XIII, 1890, p. 476. 



