WARBLERS. 63 
and habits, deserves honourable mention by reason 
of its fondness for many more or less destructive 
insects, by whose slaughter it earns a just claim to 
our favourable consideration. It is especially fond 
of the leaf-rolling caterpillars which often cause so 
much mischief, and may be seen busily at work upon 
a sunny day, flying round and round the tree, and 
picking off the destructive grubs as they hang sus- 
pended from the boughs by their silken threads. The 
green oak moth, too, whose mischievous character 
has already been described, is a favourite morsel with 
the bird, which is, therefore, a prominent factor in 
the task of preserving our oak woods from destruction. 
PassinG by the Black-cap, which, although in great 
measure insectivorous, calls for no special mention, 
the Nightingale next claims our attention. 
Fortunate indeed is this among birds, for, although 
it is a somewhat frequent visitor to the fruit garden, 
the beauty of its song saves it from serious persecu- 
tion. On the other hand, however, it destroys an 
immense number of insects, and so more than com- 
pensates for its occasional robberies. 
Prevost Paradol’s investigations with regard to the 
diet of the nightingale give the following results :-— 
‘¢ April, flies, beetles, and worms ; May, butterflies, 
weevils, cockchafers, and grubs; June, spiders and 
wood-boring beetles; July, worms, grubs, grass- 
hoppers, moths, and flies; August, grasshoppers, 
glow-worms, weevils, and grubs.” 
Against all this we have to set only the relatively 
F 
