AVES. 291 



have been accomplished, and it even appears to happen occasionally that a 

 bachelor bird sings all summer apparently for his own exclusive amusement. 

 Mr. Broderip, in Zoological Recreations, mentions a case of this kind as 

 follows : " We have heard the wild thrush, one of the sweetest singers of his 

 tribe, sing far into September, but we watched narrowly and never could find 

 that he had a mate." He Avas either too much of a genius to be troubled with 

 the cares of ornithological matrimony, or was culpably unambitious about 

 perpetuating the ancient house of the Thrushes. 



Many birds Avhich have no song possess notes of remarkable beauty and 

 purity of intonation. 



It appears to be nearly or quite impossible to set to music any length- 

 ened song of a bird. This is owing to its being, as tei*med by musicians, 

 out of time. This remark does not imply, however, to some birds which have 

 a few melodious notes ; these can often be accurately recorded, though it 

 must be borne in mind that it is nearly impossible to imitate them with any 

 ihstrument. 



Nearly all birds can be taught strains other than their natural notes, by 

 the. more or less long continued repetition of such in their hearing ; and 

 several families, especially of the Parrots, can be taught to imitate the human 

 voice with considerable success. No animals CxXcept birds are capable of 

 this kind of imitation. The strength and compass of a bird's voice depend 

 on the size and proportionate force of the larynx. The male only possesses 

 this organ in sufficient development ; in the female it is weak and small. It 

 is found by experiment that this organ may be greatly improved in all singing 

 birds by exercise and habit, so as to greatly enlarge and improve the song. 

 Nutritive food, fresh air, and exposure to sounds which excite attention and 

 emulation, in the season of courtship especially, are productive of this effect. 



The highest degree of merit as a songster, from time immemorial and by 

 universal assent, has been awarded to the nightingale, of which we shall speak 

 at length in its proper place, and also of the greatest of our American song- 

 sters, the mocking-bird. 



In the economy of the bird the bill is, perhaps, the most important organ, 

 as it not only performs the offices of the jaws in other animals, to some 

 extent, but is also a substitute in a great measure for the hand or fore paw 

 of other vertebrata. It has considerable analogy, however, to the length- 

 ened snout of the crocodiles, or the long-nosed fishes or quadrupeds. .By 

 this organ the food is seized in all birds, and in rapacious birds it is con- 

 structed for tearing their prey in conjunction with the feet and claws, and such 

 is the case also so far as relates to many of the small insect-eating birds. 

 Some birds, the horn-bills {BiiceridcB) for instance, have large and grotesque 

 appendages to this organ, the uses of which have never been ascertained. (See 

 •pi. 1^% jig. 2). 



The possession of wings is the most peculiar character of birds amongst 

 the vertebrated animals, but in several groups these members are so 

 materially modified as to be almost useless. In very many of the Galli- 

 naceous birds, which comprise the common fowls, the pheasants, quails, 

 &c. {pi. 96), the wings are so short and weak as to be only capable of 



495 



