WILD DUCKS OF THE BEAR RIVER MARSHES, UTAH. 11 
weed (Potamogeton pectinatus), known familiarly to hunters as 
" potato moss " or " duck moss," is the dominant plant of the open 
bays and sloughs, where it grows submerged in the water. This 
plant springs from a tuber buried from a few inches to a foot or 
more in the mud. It appears in the bays in abundance during 
the last part of May and by the end of June has filled the greater 
part of the open water with dense growth. During July it produces 
a mass of hard seeds, and then a great deal of it dies down in the 
bays at the mouth of the river and breaks off at the roots, to drift 
out into the lake and leave the bays bare open expanses with a 
smooth mud bottom. In other places, as the Chesapeake Bay. the 
summer growth sinks to the bottom and remains throughout the 
fall. The sago pondweed is one of the best of known duck foods, 
as all parts of the plant, the tubers, steins, leaves, and seeds are 
palatable and are eagerly sought as food by wild ducks. The ducks 
dig great "duck holes" in the mud of the open bay from 1 to 20 
or 30 feet wide and from a few inches to a foot deep, in search of 
the succulent tubers. These roots furnish a great part of the food 
of the pintails and mallards on the marsh in fall and are eaten 
eagerly by most if not all of the other clucks. In summer and early 
fall the stems and leaves also are sought. 
Sago pondweecl seems to be strongly resistant to the action of al- 
kalis, as it will grow in areas where the soil is impregnated with 
salts, though in such places the growth of the plant may be some- 
what stunted. This plant also thrives in the fresher water of channels 
and sloughs, and here makes a very heavy growth. Its tubers are 
frequently as large as a kernel of corn, and, if the sprout is discarded, 
they have a pleasant, nutlike flavor. They persist even during years 
when the bays are dry during summer, and so insure a supply of this 
food the following year. After the plants have died down in the 
lower bay the seeds still remain, and often are washed up in long 
windrows on the mud bars. Green-winged teals as well as other 
ducks are fond of these, and in fact hardly a duck stomach was 
examined in late summer and fall that did not contain a few of them. 
Bits of gravel or other hard particles are essential to digestion of 
food in ducks, but in alluvial deposits like those at the mouth of 
Bear River, situated far from the foothills, small pebbles and grit 
are difficult to secure. The hard seeds of the " potato moss " are 
firm enough to aid in grinding up other softer foods, while at the 
same time they are themselves digested, so that they serve a double 
purpose in the economy of the birds concerned. 
The second plant, equal in importance as a duck food to the one 
just described, is the bayonet grass, rush, or tule (Scirpus paludosus). 
(PI. Ill, fig. 1.) This is the dominant plant of the marsh growth and. 
except where saline conditions in the soil are too strong, covers the 
