WARBLERS. 79 



nature : to them appears intrusted the subjuga- 

 tion of those innumerable minute insects which 

 lurk within the buds, the foliage, or the flowers, 

 of plants, and, thus protected, escape that de- 

 struction from Swallows to which they are ex- 

 posed only during flight. The diminutive size 

 of such insects renders them unfit for the nourish- 

 ment of the Thrushes and the larger insectivor- 

 ous birds; while their number and variety only 

 become apparent when the boughs are shaken and 

 their retreat disturbed. How enormous, then, 

 would be their multiplication, had not nature 

 provided other races of beings to check their in- 

 crease. No birds appear more perfectly adapted 

 for this purpose than are the Warblers." Mr. 

 Swainson goes on to notice the arrival of these 

 birds in spring, when the increasing warmth is 

 calling the insect world into renewed life and 

 activity, and their departure in autumn, when the 

 hosts of minute insects begin to diminish, and no 

 longer require to be kept within bounds. As 

 different localities seem allotted to different tribes 

 of insects, so similar diversity is observable in the 

 haunts of the various groups of Warblers. Thus 

 the Golden-crests and Wood-warblers (Sylvi- 

 ance) confine themselves principally to the higher 

 trees, where they search for winged insects 

 among the leaves, or capture them like the Fly- 

 catchers, when attempting to escape. The Reed- 

 warblers and the Nightingales (Philomelince) 

 haunt the vicinity of waters, or the more dense 

 foliage of hedges, for insects peculiar to such 

 situations. The Stonechats (Saxicolina), on the 

 contrary, prefer dry commons, and wide extended 

 plains, feeding on insects appropriated to those 



