91 



glided with their wings pointed downward at a sharp 

 angle. In the narrative I have recorded my impres- 

 sion of their booming. 



Rhoads saw only two or three Nighthawks in Febru- 

 ary, 1905, when the majority of the birds may have 

 been in a more southern latitude. They arrive in 

 the Imperial Valley each spring about the middle of 

 March. 



75. Calypte costae. Costa's Hummingbird. — One of these 



hummers was observed poising before a white lily 

 near the Tres Pozos, on April 9. Rhoads collected 

 two at Mount Mayor, and wrote, ''These tiny birds 

 were breeding, one of the specimens shot showing 

 bodily marks of protracted incubation on the 21st of 

 February." 



76. Selasphorus rufus. Rufous Hummingbird. — One col- 



lected in the Cocopahs by Rhoads. He writes, ''This 

 bird was going through its aerial love antics in Febru- 

 ary with all the energy of a midsummer madness. 

 This was the more remarkable as all other bird and 

 animal life was in its deepest winter lethargy during 

 my entire stay at this camp, and the temperature 

 frequently fell to near 45°." 



77. Tyrannus verticalis. Arkansas Kingbird. — One speci- 



men, a breeding male, taken near the Hardy on April 

 1. Observed only in the bottom-land along the river. 



78. Myiarchus cinerascens cinerascens. Ash-throated 



Flycatcher. — Observed occasionally all along our 

 route, but particularly common in the Wash Associa- 

 tion on the western slopes of Pattie Basin. Here, in a 

 locality at least ten miles from water, the Ash- 

 throated Flycatchers were conspicuous in the mesquite 

 and ironwood trees that margined the arroyos. Three 

 breeding males were shot here on April 7, and a 

 female was taken at the edge of the desert south of 

 Mexicali on April 19. 



All four specimens are smaller in the dimensions of 

 wing and tail than the mean of a series of twenty-five 



