126 FACULTIES OF BIRDS, 



an organ substances which can only be subservient 

 to the functions of that organ, should we deny them 

 that use, although the part can do its office without 

 them? The stones assist in grinding down the 

 grain, and by separating its parts allow the gastric 

 juice to come more readily in contact with it*.'* 



*' Very few of the soft-billed birds," says the Hon. 

 and Rev. W. Herbert, " eat gravel : the nightingale 

 never, nor does the redstart. The whinchat in con- 

 finement will sometimes swallow stones as large as 

 swan-shot, which pass through very soon ; but he 

 seems to eat them like a fool, taking them for victuals, 

 in the same manner as I have seen tame redstarts, 

 which do not naturally choose vegetable food, swallow 

 green peas, after passing several minutes in trying to 

 kill them. But these birds have the power of ex- 

 pectorating the shells and hard parts of insects which 

 they cannot digest, throwing them off in little oval 

 balls. Young birds before they feed themselves 

 appear to be endowed with powers of digestion which 

 they do not afterwards retain. There is no difficulty 

 in rearing any young Sylvia till they are full grown ; 

 but after this period the difficulty of preserving them 

 by artificial food commences. The redstart gives to 

 its young such beetles as the aged bird is afraid of 

 swallowing. It feeds its young entirely with flies 

 and coleopterous insects. The brown wren does the 

 same, often giving them the large lambda moth. 

 The yellow wren gives aphides and small green cater- 

 pillars. Full grown white-throats, which have been 

 reared in a cage, at the sight of a green caterpillar 

 immediately perk up their heads, and cry etchat, 

 etchat. Tame Sylvice are such fools that if the floor 

 of their cage is cleaned by a flannel rubber or woollen 

 mop, they eat the woollen hairs which form an indi- 

 * On the Animal Economy, p. 196-8. 



