J^ebraska Ornithologists' Union, 55 



on the bird population. However, the Killdeer has been 

 found nesting in such a situation. Certain of the valleys 

 undoubtedly contain enough moisture in the early spring 

 to affect the migrating visitors but during the nesting 

 season they are usually dry and cannot be considered un- 

 der the present heading. 



4. Lakes — Although present in many parts of the sandhills, 

 lakes are absent in the territory embraced by this paper. 



5. Ranch buildings. — The artificial conditions imposed by 

 ranch buildings probably affect bird life in the hills as well 

 as in the valleys, but in the absence of any such building in 

 the portion of the hills which I explored, I am unable to 

 give any data on this particular habitat. 



6. Planted groves. — Pine groves are not a natural habitat 

 of sandhill country nor yet an ordinary artificial one, but 

 the presence of a pine-covered area so large as that on 

 the Eeserve will, someday, in all probability, furnish con- 

 ditions not to be disregarded in a consideration of the 

 biology of the region. Even now there is an appreciable 

 effect on the entomology of the place, but the trees are 

 mostly of such small size and of so recent establishment 

 that as yet little influence is to be noted on the bird life 

 of the region during the breeding season. It is hardly 

 possible that the occurrence of the Audubon Warbler and 

 Rocky Mountain Bluebird, both residents of pine-covered 

 territory, can be attributed to the presence of the conifers 

 on the Reserve, especially since neither bird was seen in 

 the planted areas. 



No groves of deciduous trees were found which were 

 of undoubted artificial origin. One or two were visited 

 which might have been planted but they presented no 

 features which distinguished them, ornithologically 

 speaking, from some of the larger natural groves. One 

 nest, evidently that of a Swainson Hawk, although not 

 definitely so determined, occupied a tree in one of these 

 places. No other possibilities in the nature of breeding 

 birds were noted. 



B.— PRAIRIE ( CAROLINIAN) . 



I. Larger streams with sandy mud Hats and sandbars. — This 

 habitat is furnished by the Middle Loup and Dismal rivers, 



