370 BULLETIN 179, UNITED STATES NATIONAL MUSEUM 



"olive-brown"; on two of the eggs there is a concentration of spots 

 of darker brown and drab in a wreath about the larger end. Probably 

 a larger series of eggs would show the usual variations in colors and 

 markings seen in the southwestern races of the species. The meas- 

 urements of 31 eggs average 21.4 by 15.7 millimeters; the eggs 

 showing the four extremes measure 23.2 by 15.5, 20.9 by 16.6, 19.4 by 

 14.8, and 19.8 by 14.4 millimeters. 



Fall. — Referring to the vicinity of the Huachuca Mountains, Harry 

 S. Swarth (1904) writes: "Toward the end of July and early in 

 August, young and old gathered together in immense flocks, and 

 were at this time very restless and difficult to approach, flying a long 

 distance when disturbed. They seemed to depart for the south soon 

 after, for on September 5, 1902, on a drive of over twenty miles over 

 country in which they had bred in the greatest abundance, not a 

 single Horned Lark was seen," Later he says (1929) : "In the fall 

 there proved to be but a small proportion of odusta among the enor- 

 mous flocks of homed larks that frequented the plains." The 

 predominant number of occidentalis at that season indicated "a de- 

 serting of the breeding grounds by odusta during the winter months." 



OTOCORIS ALPESTRIS AMMOPHILA Oberholser 



MOHAVE HORNED LARK 



HABITS 



In describing and naming this subspecies, Dr. Oberholser (1902) 

 states that it is like 0. a. actia but "may be easily distinguished by 

 its very much paler color above, while its decidedly smaller size, con- 

 spicuously more cinnamomeous shade of nape, upper tail-coverts and 

 bend of wing render it readily separable from leueolaema. Compared 

 with occidentalis it is paler, of smaller size, with the cervix, upper 

 tail-coverts, and bend of wing more cinnamomeous, the upper surface 

 less uniform. It is somewhat smaller than adwsta and paler, par- 

 ticularly in winter, with the back scarcely or not at all reddish, the 

 demarcation line between cervix and back usually well marked. 

 * * * The young of ammophila differ markedly from the young 

 of actia in their paler, much more grayish upper parts; being prac- 

 tically indistinguishable from leucolaema of the same age." 



This subspecies occupies, in the breeding season, a rather limited 

 range in the desert regions of southeastern California, from the 

 Mohave Desert northward to Owens Valley. Dr. Oberholser (1902) 

 says : "This desert race seems to be most typical in the region imme- 

 diately southwest of Death Valley, California, whence a good series 

 of specimens was brought back by the Death Valley expedition of 

 1891. The breeding birds in this series were identified as arenicola 

 { = leuGolae7na) ^ the winter specimens as chrysolaema {= actia) y 



