WATEEFOWL IN NEBRASKA. 11 



(3) The Cody Lakes. 



(4) Lakes of Brown County. 



(5) Lakes of Garden and Morrill Counties. 



Many of these lakes are more or less ephemeral, though in recent 

 years the area of a number of the larger lakes has grown and the 

 permanency of the smaller ones inclined to become more certain. 

 During unusually rainy seasons the number of temporary ponds is 

 greatly increased, and sometimes these exist even among the sand- 

 hills themselves. All these lakes are relatively small, most of them 

 not over three or four miles long, the largest not over seven miles; 

 and they vary from this down to bodies of water of not more than an 

 acre or two, though few of the smallest are permanent. All are 

 relatively shallow, ordinarily not over a few feet in depth, the 

 greatest depth in any being not over 18 or 20 feet. The water of most 

 of them is fresh, or nearly so, but in a few is rather strongly alkaline. 

 Most of the lakes have no outlet except at very high water, and many 

 of them not even then. 



With regard to the character of their shores, these lakes may be 

 divided into four categories: (1) those in which the water is wholly 

 or largely covered with vegetation; (2) those with a moderate 

 amount of marsh or other vegetation growing in the water; (3) 

 those with wholly grassy shores but with little or no visible vegeta- 

 tion in the water; and (4) those with sandy shores and with little or 

 no vegetation growing in the water. Of these four the first two are 

 as a rule most favored by ducks, though on some of the lakes of the 

 other two many ducks are sometimes found. 



The vegetation of these lakes, aside from the grassy turf which 

 forms the margin of many, consists chiefly of various kinds of 

 sedges, rushes, and coarse grass, growing chiefly in the water; on 

 some there are also more or less extensive areas grown up to wild 

 "cane" {Phragmites communis)^ cat-tails {Typha latifolia)^ and 

 wild rice {Zizania palustris), together with yellow waterlilies 

 {Nymphaea advena). These and other plants which furnish food 

 for the ducks are dealt with in Part II of this report. 



The few perennial streams of the sandhills, chiefly the heads of 

 rivers, flow, except for the marshy vallej^s at or near their sources, 

 through canyons which they have cut for themselves in the plain. 

 Most of these canyons, however, are narrow and not of great depth. 

 Within the sandhill region proper there is little vegetation along 

 these streams, though at its edge and in the plains country sur- 

 rounding it the canj^ons are usually more or less heavily wooded 

 with oaks, pines, elms, junipers, and other similar trees. In fact, 

 about the only trees of any consequence in the sandhills are the 

 cottonwoods that have been planted about the lakes and near ranches. 



