BIEDS OF THE PAPAGO SAGUARO NATIONAL MONUMENT. 23 



passage, of birds at any rate, yet with nothing in common in the 

 animal and plant life of the two regions. 



As an object lesson in the puzzling problem of the distribution 

 of animals and plants, it is well worth while to turn aside from the 

 sameness of the highway through the valleys, travel 20 miles into 

 these mountains, and see the changes accompanying a drop in tem- 

 perature of but a few degrees. Fifty-seven species of birds were 

 observed in the Transition Zone of the Sierra Ancha during June; 

 52 about Roosevelt Lake. Only 14 species were noted at both places. 

 Of these 14, one (the desert quail) has been artificially introduced 

 at a ranch in the mountains; two (western wood pewee and western 

 tanager) were belated migrants in the valley, on their way to the 

 mountains, and the others aYe wide-ranging species, such as the 

 mourning dove, turkey vulture, and western re4-tailed hawk. \For 

 the most part the avian assemblages of the two regions are wiojely 

 different, thouglT in"fiianycases closely related species replace' one 

 another in mountain and valley. Thus there may be contrasted, in 

 the pines of the Sierras and in the valley, respectively, band-tailed 

 pigeon and white-winged dove, red-shafted flicker and gilded flicker, 

 broad-tailed hummingbird and costa hummingbird, Cassin king- 

 bird and western kingbird, mountain towhee and canyon towhee, 

 violet-green swallow and rough-winged swallow, Virginia warbler 

 and Lucy warbler, western gnatcatcher and plumbeous gnatcatcher, 

 to mention some of the more conspicuous. 



There are some of the mountain birds that are certain to attract 

 the attention of even the most casual observer, while many others 

 must await the more careful search required for their discovery. 

 The Sierra Ancha constitute one of the few remaining retreats of 

 the wild turkey, and in these mountains this species still occurs in 

 sufficient numbers to guarantee its continued existence as a game 

 bird, provided it receives adequate protection. In June the broods 

 of young were beginning to appear. 



Another fine game bird, the band-tailed pigeon, occurs in fair 

 numbers in the higher parts of the range. Usually the first intima- 

 tion received of the proximity of pigeons is the loud clapping of 

 wings as the birds hurriedly take flight from some oak tree when 

 approached too nearly. Now and then a small flock or a single 

 bird is seen high in the air, crossing from one hillside to another, 

 and occasionally a male bird may be observed going through his 

 courting evolutions. In this performance the bird launches into the 

 air from his perch on some tall tree, and, with wings and tail stiffly 

 outspread, describes a large circle back to his starting point. During 

 this flight he utters a wheezing noise, not audible at any great dis- 

 tance. 



