252 PASSERES : Perching Birds 



WESTERN BLUEBIRD 



(767. Sialia mexicana occidentalis) 7 in. 



Male: Dark blue, except chestnut on shoulders (often meeting 

 on back), sides, and breast. 



Female: Rump and tail blue; otherwise blue of male is re- 

 placed by gray; brownish on back, rusty- washed below. 



Juvenile: Wings and tail blue; back dark brown, white- 

 streaked; breast streaked white and brown. 



Nest in a natural tree-cavity or old Woodpecker-hole. 



Includes San Pedro Bluebird (No. 767b.) not generally 

 recognized. 



CHESTNUT-BACKED BLUEBIRD 



(767a. Sialia mexicana bairdi) 7 in. 



Like the Western in every way except that fore-back is solid 

 chestnut instead of having contiguous chestnut patches. 



MOUNTAIN BLUEBIRD 



(768. Sialia currucoides) 7 in. 



Male: Greenish blue; lighter below, changing to white on belly. 

 Duller in winter, when blue of upper parts is partly obscured by 

 brown tips. 



Female: Wings and tail blue, otherwise brownish gray above; 

 below, pale blue overcast with brownish. 



Juvenile: Wings and tail blue; head and neck gray; back and 

 breast streaky brown and white. 



In feeding, hovers hawk-like, twenty to forty feet in air, 

 inspecting the ground below. 



