14 SAXICOLIDiE SIALTA MEXICAN A SIALIA ARCTICA. 



SIALIA MEXICANA, Sw. 



Western Bluebird. 



Sialia mexicana, Sw., F. B. A. ii, 1831, 202.— Bp., List, 1838, 16.— Bd., B. N. A. 1858, 

 223; Rev. 1864, 63.— Kexn., P. E. R. Rep. x, 18.j9, pt. iv, 23.— IIeerm., ibid. 

 pt. vi, 43.— Coop. & Suck., N. II. Wash. Ter. 1860, 173.— Scl., P. Z. S. 18.59, 

 362 (Xalapa); 1856, 293 (Cordova).— Coxtes. Pr. Phila. Acad. 1866, 66 (Ari- 

 zona). — Coop., B. Cal. 1870, 28. — Sumich., Mem. Bost. Soc. i, 1869, .544 (Vera 

 Cruz, alpiue). — Coop., Am. Nat. iii, 1869, 32 (Montana). — Coop., Pr. Cal. Acad. 

 1870, 75 (Colorado River).— Aiken, Pr. Bost. Soc. sv, 1872, 194 (Eastern Col- 

 orado). — Allen, Bull. M. C. Z. iii, 1872, 174 (Denver, Colorado). — Coues, Key, 

 1872, 76. 



Sialia occidentalis, Towns., Journ. Phila. Acad. 1837, 188. — AuD., B. Am. ii, 1841, 176, pi. 

 135.— NuTT., Man. i, 2d ed. 1840, 513.— Woodh., Sitgr. Rep. 1853, 68 (New 

 Mexico).— Newb., P. R. R. Rep. vi, 18.57, 80. 



Sylvia occidentalis, Aud., Oru. Biog, v, 1839, 41, pi. 393. 



Sialia cairnhicolUs, ViG., Zool. Beechey's Voy. 1839, 18, pi. 3. 



Hal). — United States, from the eastern foot-hills of the Rocky Mountains to the Pacific. 

 Mexico. 

 Not procured by any of the Expeditions. 



The Western Bluebird apparently inliabits only a limited area in the 

 sonthwestern part of the Missouri region. Mr. Ridgway informs me of 

 its occurrence in Iowa, but this must be higlily exceptional. It has not 

 been observed by any of Dr. Hayden's parties in regions where aS'. arctica 

 is abundant, nor have 1 seen it myself anywhere along the Missouri. 

 Mr. Allen and Mr. Aiken both report it from Eastern Colorado, where it 

 is abundant, as it is also along the Pacific slopes to a higher latitude 

 than it has been observed to reach in the interior. I found it resident 

 and abundant in the mountainous portions of Arizona. Since, according 

 to Mr. Ridgway, it is apparently absent from the Great Basin, it would 

 seem to have two divaricating lines of migration, one carrying it far 

 along the Pacific slopes, and the other taking it not so far along the 

 main chain of the Eocky Mountains. In both cases it chooses wooded 

 as well as mountainous regions. In its habits it is the counterpart of 

 its familiar Eastern relative. 



SIALIA ARCTICA, Sw. 



Rocky Mountain Bluebird. 



Erythaca (Sialia) arctica, Sw., F. B. A. ii, 1831, 209, pi. 39.— Ricii., List, 1837. 



Sialia arctica, Nrxx., Man. ii, 1834. 573; 2d ed. i, 1840, 514.— Bp., List, 1838, 16.— AuD., 

 Syu. 1839, 84 ; B. Am. ii, 1841, 178, pi. 136.— McCall, Pr. Phila. Acad. 1851, 

 215.— Woodh., Sitgr. Rep. 1853, 68.— Bd., B. N. A. 1858, 224; Rev. 1864, 64; 

 P. R. R. Rep. X, 1859, pt. iii, 13, pi. 35.— Kenx., ibid. pt. iv, 24.— Heeem., 

 ibid. pt. vi, 44.— Hayd., Rep. 1862, 159.— Coues, Pr. Phila. Acad. 1866, 66— Coop., 

 Am. Nat. iii, 1869, 32 ; Pr. Cal. Acad. 1870, 75 ; B. Cal. 1870, 29.— Stev., U. S. 

 Geol. Surv. Ter. 1870, 463.— Merk., ibid. 1872, 671.— Allen, Bull. M. C. Z. iii, 

 1872, 174.— AiKEX, Pr. Bost. Soc. xv, 1872, 194.— Coues, Key, 1872, 76. 



StjMa arctica, Aud., Orn. Biog. v, 1839, .38, pi. 393. 



Sialia macroptera, Bd., Stausbury's Rep. 1852, 314. 



Hab. — Eastern foot-hills of the Rocky Mountains to the Pacific, chiefly in mountainous 

 regions. North to 64^° ; south to Mexico. Less common on the Pacific slopes, where 

 S. mexicana prevails. 



List of specimens. 



10194 

 19339 



Snake River.. . 

 Bighorn River . 



June 15, 1860 

 June 6,1860 



F.V.Hajden. 

 G. H. Trook.. 



7.00 

 7.00 



13.50 4.50 

 12.50 4..''>0 



Lieutenant Warren's Expedi1ion.—8883-d0, Black Hills. 



Later Expeditions. — 60434, Bitter Cottonwood Creek; 60682-6, Fort Bridger, Sweet- 

 water, and Uintah Mountains; 60939-47, Green River, &c. ; 61164, Wyoming {Schmidt 

 aud Stevenson). 62330-2, Idaho and Wyoming (Merriam). 



