LIST AND DESCRIPTION 137 
768. Mountain Biuesirp (Sialia currucoides.) 
This exquisite bird, sometimes called Arctic or Rocky 
Mountain Bluebird, belongs to the mountains and the intermoun- 
tain plateaus. It is found within the State, therefore, only in 
the Black Hills and in the badland areas. It lacks the chestnut 
breast of its eastern cousin and is of a lighter blue. On seeing 
this bird for the first time one goes into transports of delight. 
It is like a winged bit of sky from the snow crowned peaks 
where the sky is purest. And, as though to accentuate its beauty, 
it has a delightful habit of poising like a Hummingbird on 
wing while watching for insects in the grass. 
