424 NATURAL HISTORY. 



of themselves ; others demand the mother's attentions. At various times 

 during life the feathers are changed. "When fullv formed, a feather is no 

 longer capable of any alteration, or even of being repaired in the case of 

 any injury; and so this feather-changing — molting, it is called — plays an 

 important part. In some birds the operation is a gradual one, one feather 

 after another being dropped, and new ones taking their place in the same 

 order; while in others, so many may be lost at once as to make the bird 

 unable to fly. With these molts are frequently connected changes in the 

 colors of the plumage, often of great extent. 



Of all groups of the animal kingdom there is none which excites the 

 same amount of interest that the birds do. Their graceful shapes, their 

 bright colors, and their interesting habits, render them fit subjects for 

 both the painter and the poet ; and the amount of extravagant writing 

 they have inspired is almost incredible. Yet as one studies the resplen- 

 dent colors of the humming-birds, or watches the majestic flight of the 

 birds of prey, he can pardon any use of poetic license ; for, be as extrava- 

 gant as one can, no description and no figure can equal nature. 



This interest in birds has resulted in a literature perfectly enormous, 

 the extent of which one cannot begin to realize until he stands in the 

 alcoves of a scientific library, and sees shelf after shelf and case after case 

 filled with books, some small, others large quartos and folios, all devoted 

 to the description of the appearance and habits of our feathered friends. 

 Some are extremely technical in character, giving long-winded descriptions 

 of feathers and bills, bones and muscles ; while others — far more inter- 

 esting — go to the other extreme, and give the songs, the nesting habits, 

 and long and charming accounts of the psychological side of bird life. 

 These works, too, have an artistic side ; for most of them are illustrated 

 with plates, the production of which calls for the highest skill of the 

 artist and the engraver. No other class of books in the whole range of 

 literature equals the books on birds in this respect. 



Some Old-Fashioned Birds. 



One of the rarest and at the same time most interesting of fossils is 

 the curious form represented in our figure. It is rather mixed up; but 

 still it reveals some very interesting features, the most striking of which is 

 the long-feathered tail which extends from the centre of the cut down 

 towards the bottom of the picture. Now, in all modern birds the tail 

 is extremely short, and consists of but a few bones welded together; but 

 here is a bird with a long tail like that of a reptile, except that it is 

 feathered on either side. No living bird has teeth; but in other specimens 





