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U. S p. R. R. EXP. AXD SURVEYS — ZOOLOGY — GENERAL REPORT. 



List of specimens. 



SIALIA AKCTICA, S ^v- a i n s o n . 



Rocky JUountaiu Blue Bird. 



Erijthraca {Sialia) arctica, Swainson, F. Bor. Araer. 11, 1831, 209 ; pi. xxxix, 



Erythraca arclica, Rich. List, 1&37. 



Sialia arctica, Nuttall, Man. 11, 1832, 573 ; I, 2d cd., 1840, 514.— Bonap. List, 1838.— Acd. Synopsis, 1839, 84.— 



1b. Birds Amer. II, 1841, 178 ; pi. 136.— McCall, Pr. A. N. Sc. V, June, 1851, 215. 

 Sylvia arctica, Addubon, Orn. Biog. V, 1839, 38 ; pi. 373. 

 Sialia macroptera, Baird, Stansbury Report Exp. Salt Lake, 1852, 314. 



Sp. Ch. — Azure blue above and below, brightest above ; the belly and under tail coverts white : the latter tinged with blue 

 at the ends. Female showing blue only on the rump, wings, and tail ; a white ring round the eye ; the lores and sometimes a 

 narrow front whitish ; elsewhere replaced by brown. Length, 6.25 ; wing, 4.36 ; tail, 3.00. (1875.) 



Hab. — High dry ccntrnl plains ; Upper Missouri to Rocky mountains range and south to Me.i;ico. Rare on the coast of 

 California. 



In this species there is none of the reddish brown of the two other American blue birds, the 

 color throughout being blue, except as mentioned. The shade of blue is much lighter, with 

 more green in it, or smalts-color, especially on the crown, instead of the purplish blue of the 

 others. The shade on the under parts is paler than above ; it extends entirely along the sides 

 and to the abdomen. 



The female has the abdomen and under coverts like the male ; the remaining under parts, 

 with the head, neck and back, arc light brown, although a bluish shade is appreciable on 



