BLACKBIRD. 



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 previously stated 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 Cyclopaedia 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 and re- 

 newed by pairs. 



" Although the feathers of birds appear to be an entire 

 and uniform covering, they do not arise equally from every 

 part of the body, but only from such parts of the skin as 

 are least liable to be affected by the motion of the conti- 

 guous parts, such as the action of the limbs. 



VOL. I. Q 



