BLACKBIRD. 215 



coloured spots ; belly, sides, and under tail-coverts, hair- 

 brown. 



The young have the upper parts blackish brown, darker 

 in the males, each feather having a central spot or streak of 

 pale rufous : under parts light rufous brown, with terminal 

 dark spots, generally more distinct in the males. 



Young males having completed their first autumn moult, 

 are intermediate in the general colour of their plumage be- 

 tween that of the adult female and adult male, the yellow 

 also beginning to appear at the point of the beak. 



Having stated at page 166 some of the laws which appear 

 to govern the assumption and changes of colour in the 

 plumage of birds, I may here add a few remarks on the 

 disposition and situation of the feathers themselves. It is 

 not, however, my intention to attempt to describe the 

 structure and growth of a feather, one of the most com- 

 plicated of all the various productions of the skin in 

 animals ; such minute anatomical details would be out of 

 place in a work intended to be popular, but the reader 

 who is inclined to pursue this part of the subject may con- 

 sult with advantage the " Developement of Feathers," by 

 F. Cuvier, in the Memoires du Museum, torn xiii ; or the 

 article " Aves," in the first volume of the Cyclopsedia of 

 Anatomy and Physiology by Professor Owen. 



In young birds the first feathers are preceded in their 

 passage through the skin by filaments of down ; but after 

 the first plumage, at the regular period of moulting, each 

 old feather is the pioneer of that which is to follow. 

 The natural moult proceeds by degrees, and the large 

 quill-feathers of the wings and tail are generally shed by 

 pairs. 



" Although the feathers of birds appear to be an entire 

 and uniform covering, they do not arise equally from every 



