BO6K OF MiGRATORV BIRDS 143 



In the plumage of the first year, when it is known 

 under the name of Black-billed Auk, the bill is very weak, 

 and the indication of the white streak to the eye is just 

 marked ; the upper parts are as in the adult breeding state, 

 but without the lustre ; while the chin, throat, cheeks, and 

 sides of the head, as well as the under parts, are white; 

 the light colour passing over nearly to the occiput, where 

 it is very slightly clouded, and the feathers become gradu- 

 ally purer, the tips for a certain space only being dark. 



