DESCRIPTION AND DISTKIBUTION OF S. AKCTICA 83 



9 Grisea, tiroptjgii), caudd alisque cwrulescentibus ; infra rufo- 

 grisea, abdomine albicante. 



$, iu perfect plumage: Above rich azure-blue, lighter than in the two 

 foregoing, and with a faint greenish hue; below, paler and more decidedly 

 greenish-bine, fading insensibly into white on the belly and under tail- 

 coverts. Ends of wing-quills dusky ; bill and feet black. Larger than the 

 two foregoing species; length, 7 or more; extent, about ]3; wing, 4| ; 

 tail, 3. 



2 : Of a nearly uniform indeterminate rufous-gray, lighter and more de- 

 cidedly rufous below, brightening into blue on the rump, tail and wings, 

 fading into white on the belly and under tail-coverts. Ends of the tail- 

 feathers as well as of the wing-quills fuscous ; outer one of each edged 

 with whitish. A whitish eye-riug. 



Young : The changes of plumage with age as well as those with season 

 are parallel with the stages exhibited by the other species. Very young 

 biids, in the streaky stage, are distinguished by their superior size and the 

 greenish hue of the blue on the wings and tail. The inner wing-quills in 

 the specimens before me are edged and tipped with a-v hitish instead of rufous. 



IX the preceding notice of 8. mexiccuia, I have already 

 alluded to some points in the distribution of this species, 

 and little remains ^o be said. It is notable as the most north- 

 erly representative of the genus, reaching latitude 64° 30', or 

 about fourteen degrees , beyond the usual range of S. sialis. 

 It would ai)pear to be also rather more decidedly migratory 

 than S. mexicana, and is extremely abundant in some regions, 

 as portions of Dakota and Montana, which the latter rarely if 

 ever reaches. It is nevertheless nuuaerous in portions of Colo- 

 rado, Utah, Nevada, and Northern Arizona and New Mexico. 

 It breeds as far south at least as Santa F6 in New Mexico; 

 winters at least as far north as Carson City, Nevada, and is 

 consequently resident in the Colorado Basin as a whole. As in 

 the case of S. mexicana, it does not seem to have any peculiar 

 habits in comparison with S. sialis. Though a good deal has 

 gone on record in both cases, the supposed discrepancies 

 may be reasonably attributed to transient circumstances of 

 observation, or the^ fluctuating standpoint of comparison as- 

 sumed. It breeds in the mountains up to aa altitude of about- 

 10,00Q feet, in holes in trees and similar nooks, just like both its 

 relatives. The eggs are of the same pale bluish color, but 

 rather larger than those of either of the other species, measur- 

 ing 0.90 to 0.95 in length by about 0.70 in breadth. 



