1562 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 3 



(Oposura, Cumpes), and the Rio Bevispe (Husebes, Grenados, and 

 Pilares) . 



Winter range. — Winters apparently over most of the breed range, 

 but in reduced numbers northward. 



MELOSPIZA MELODIA SALTONIS Grinnell 



Desert Song Sparrow 

 Contributed by Val Nolan Jr. 



Habits 



Melospiza melodia saltonis is a resident of the lower Colorado River 

 valley. The summary of its habitat in California by Grinnell and 

 Miller (1944) gives an idea of its life: "Riparian plant associations, 

 most notably those dominated by arrow-weed (Pluchea), guatemote 

 (Baccharis) and young willows, and tule beds and cattails in marshes, 

 overflow sumps and along irrigation systems. Nests are placed in 

 the vegetation above the mud which marks flood level. Development 

 of irrigation has undoubtedly increased the total population of this 

 race in the last 30 years. Although usually sharply limited to 

 water-seeking plants, and most abundant in cover growing over or 

 at the edge of water, this Song Sparrow has occasionally been noted 

 in mesquite thickets at some distance from water." 



The measurements of 40 eggs average 18.9 by 14.9 millimeters; 

 the eggs showing the four extremes measure 20.8 by 15.2, 18.5 by 

 15.5, 17.8 by 15.0, and 18.0 by 14-0 millimeters. Robert W. 

 Dickerman reports three sets of eggs of this race from Yuma, Ariz., 

 in the collection of the University of Arizona, two of which contain 

 eggs of the brown-headed cowbird. 



J. Grinnell (1909) described saltonis as resembling jallax, "but very 

 much paler throughout, the 'ground-color' being white ventrally and 

 ashy dorsally, with streakings of pale hazel; supercilliary stripe 

 wholly white; general size much less than in either M. m. jallax or 



M. m. montana." 



Distribution 



Range. — The desert song sparrow is resident in the lower Colorado 

 Valley in extreme southern Nevada (east of Searchlight), southeastern 

 California, western Arizona (east to Big Sandy River at 2,000 feet; 

 Alamo), northwestern Baja California (Mexicali, mouth of Hardy 

 River), and northwestern Sonora (Colorado River delta), extending 

 northwest through the Imperial Valley of California (Mecca, Calexico). 



Casual records. — Casual in the desert area of southeastern California 

 (Death Valley, Oro Grande), south-central Arizona (Tucson), and 

 northwestern Sonora (Sonoyta River, Caborca). 



