2C2 Scott on the Birds of Arizona. [April 



the land immediately in the vicinity of the Rillita, a small stream 

 rising in the Santa Catalina range, and rnnning thioiigh the Camp 

 Lowell Military Reseryation. It is important to notice in this 

 connection that both of these streams onl}' rise to the surface in 

 places, and except in the spring of the year their course is not 

 continuous, but more like a series of streams that vary from a few 

 3'ards to several miles in length. For instance, the Santa Cruz 

 River is continuously a considerable stream for at least fifteen 

 miles south of Tucson. About two miles below the town it dis- 

 appears, rising only in occasional small pools, until the Nine 

 Mile Water Hole is reached, where the stream again comes to 

 the surface, and soon aftei^ward is lost again in the desert be- 

 tween Tucson and the Gila River, which stream it ultimately 

 joins. On the other side of the town, and some fifteen miles 

 east, the Rillita, a small stream, flowing down from the sum- 

 mit of the Catalinas, enters Sabino Canon. In the spring it is con- 

 tinuous from its source to Camp Lowell, but beyond the Military 

 Reseryation to the westward it is lost almost at once; though 

 its covu'se may be plainly traced by the dry bed of the stream, no 

 water is to be seen, except in time of great freshets, until it joins 

 the Santa Cruz at the point indicated on the map. 



The vegetation of the great plain of Tucson is as varied as one 

 would naturally look for in a region at points well watered and at 

 others almost a desert. Along the two streams mentioned 

 are fine growths of cottonwood and sycamores, the former green 

 almost the entire year, with occasional black walnuts and alders. 

 While the mesquite is found at intervals, throughout the plain, 

 the finest growth is perhaps near or in the region immediateh' 

 adjoining the streams ; and a grove of these trees of special 

 beauty is to be found on the Santa Cruz River, where that stream 

 passes through the Papago Indian Reservation, south of Tucson. 



For long stretches on the more arid portions of the plain 

 are found a number of varieties of cholla, a kind of cactus, reach- 

 ing often the dimensions of the largest shrubs, or smaller trees. It 

 is perhaps needless to add that they are much branched, and 

 wonderfully repellant with their thousand spines, ready to resist 

 the slightest intrusion ; yet they form almost the exclusive nesting 

 place and home of a number of species of birds, as will be pres- 

 ently recorded. Such growths are to be met with particularly 

 just outside of Tucson to the eastward. 



