38 BULLETIN 794, IT. S. DEPARTMENT OF AGRICULTURE. 
So far as food conditions are concerned, therefore, the lakes of the 
sandhill region of Nebraska are well fitted to be a wild-duck breed- 
ing-ground of the first rank. 
IMPROVEMENT OF WILD-DUCK FOOD SUPPLY. 
The most notable deficiency in the above list of plants is wild 
celery (Yallisneria spiralis). This is an excellent duck food and un- 
doubtedly will grow in practically all the lakes of the sandhill region. 
It probably will grow anywhere that sago pondweed does. Chufa 
{Cyperus esculentus) also was not found among the plants collected, 
although it is especially suited to growth in sandy soil. It may be 
used to advantage as a duck food only where there are areas dry in 
summer, to permit growth of the plant, and flooded in winter, so that 
the ground may be softened sufficiently for ducks to dig the tubers. 
However, as noted above, most of the lakes of the sandhill region 
are well provided with wild-duck foods. In few cases is need of im- 
provement indicated, and the only agencies practically interested in 
improving the food supply of ducks are shooting clubs controlling 
certain bodies of water. To them it may be said that adding wild 
celery or chufas to bodies of water where conditions are suitable, or 
any of the plants in the preceding list where they do not now exist, will 
improve the feeding conditions for wild fowl. Directions for propa- 
gating most of these plants are contained in Bulletins of the United 
States Department of Agriculture, Xos. 205 and 465. 1 Further in- 
formation relating to the plants and the names of dealers in them 
will be furnished by the Biological Survey upon request. 
EFFECT OF ALKALINE CONDITIONS ON DUCK-FOOD PLANTS. 
The most important information gained in the study of the duck- 
food plants of the sandhill region relates to the comparative toler- 
ance of the different species to alkalinity of the water. According 
to Dr. E. J. Pool, " the waters of practically all of the many ponds 
and lakes contain considerable quantities of saline and alkaline com- 
pounds." 2 This being the case, and in view of the luxuriant growth 
of aquatic plants in most of the lakes, it is evident that the degree or 
quality of alkalinity of most of them is not injurious. 
The lakes examined during the present investigation that are popu- 
larly recognized as alkaline are Eat and Willow Lakes in Brown 
County ; Big Alkali, Clear, and Silver Lakes in Cherry County, and. 
to a lesser degree, Eed Willow, White Willow, and Speckelmire Lakes 
of the same county; and Moffitt, Crescent, Beaver (or Blue), Phala- 
rope, and Peterson Lakes in Garden County. 
1 Eleven important wild-duck foods, Bull. 205, U. S. Dept. Agr., pp. 25, figs. 23, May 
20, 1915 ; Propagation of wild-duck foods, Bull. 465, pp. 40, figs. 35, Feb. 23, 1917. 
2 A study of the vegetation of the sandhill* of Nebraska. Minn. Botanical Studies, 
vol. 4, Part III, p. 275, 1914. 
