170 University of California Publications in Zoology [Vol.12 



the clearer ash of the anterior lower parts, in the darker clay color 

 of the flanks, the clearer white of the belly, and the decidedly darker 

 tone of the dorsal streaking, sepia rather than bay. 



Spizella passerina arizonae Cones 

 Western Chipping Sparrow 



A single example noted February 20, on the California side, five 

 miles below Needles. On the Arizona side, among the precipitous hills 

 constituting The Needles, a large scattering flock was seen March 5. 

 The birds were foraging among the sparse creosote and Encclia bushes 

 on the steep slopes. Thereafter observed on the California side in 

 Chemehuevis Valley, at Riverside Mountain, Blythe, opposite Cibola 

 and eight miles east of Picacho (last April 18), and on the Arizona 

 side above Bill Williams River, at Ehrenberg, and ten miles below 

 Cibola. At all of these points chipping sparrows were frequently met 

 with, either in the bushy ravines among desert hills, or in the brush 

 of the different associations paralleling the river. 



I had concluded after seeing none for many days after April 18, 

 that the species had left the region about that time. But as a matter 

 of surprise the species was found once again on April 30 and May 1, 

 on the California side four miles south of Potholes. Here the birds 

 were notably common in the newly settled bottom land characterized 

 by open fields, groves of mistletoe-laden cottonwoods and intersected 

 by irrigation canals. They were in full song, and not in flocks as 

 were the last previously seen, but in pairs, on or near the ground; or 

 the males were singing alone from the bare upper branches of fire- 

 killed trees. The two males shot had their testes greatly enlarged. 

 Thus all the evidence obtained indicates that the species was breeding. 

 Yet no nest was actually found, and the previously unknown occur- 

 rence of the species in so low a life-zone brings an element of prob- 

 ability that these individuals were merely tarrying late in the region 

 before leaving for breeding grounds in a higher zone. Moreover the 

 specimens secured differ in neither coloration, general size, nor pro- 

 portions from breeding birds from the Sierras and northward. The 

 breeding of the chipping sparrow on the lower Colorado is problem- 

 atical ; if a fact, it is a remarkable instance of extreme range of a 

 species through zones from low Lower Sonoran to Canadian, inclusive. 



Thirty specimens were obtained by us (nos. 13170-13199) and 

 these show the time of the partial prenuptial molt to occupy some- 



