FOOD HABITS OF MALLARD DUCKS. 5 
For instance, Kumlien and Hollister’ state that large numbers 
of mallards wintering on the prairies of Wisconsin feed chiefly 
im 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 true. Even if mallards did feed extensively upon sprouting 
erain, 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 filled 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, Brunnchia, 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 hydropiper) 
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. Remains 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 pectinatus), 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 flexilis) 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 (Lemnacex) thickly cover the surface of the water in 
southern swamps, and coontail (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., XIIT, 1890, p. 476. 
