38 BULLETIN 794, U. S. DEPAKTMENT 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 {Vallisneria 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 

 {Cype'nis 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, Nos. 205 and 465.^ 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. R. J. Pool, " the waters of practically all of the many ponds 

 and lakes contain considerable quantities of saline and alkaline com- 

 pounds." ^ 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 Rat and Willow Lakes in Brown 

 County ; Big Alkali, Clear, and Silver Lakes in Cherry County, and, 

 to a lesser degree, Red 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, flg-s. 23, May 

 20, 1915 ; Propagation of wild-duck foods, Bull. 465, pp. 40, figs. 35, Feb. 23, 1017. 



2 A study of the vegetation of the sandhillfi of Nebraska. Minn. Botanical Studies, 

 vol. 4, Part III, p. 275, 1914. 



