Nature's Militia 321 



about 2,000 green -fly from the rose-trees in a green- 

 house in the course of a few hours. 



The titmouse is another most active little bird, 

 constantly engaged in the hunt for food, creeping into 

 rolled-up leaves, and devouring by the thousand eggs 

 which would produce many more hairy caterpillars 

 than the cuckoos could dispose of. As an example of 

 the invaluable services which it renders in effecting a 

 clearance of these, we may mention a garden whose 

 trees one year were entirely stripped by caterpillars. 

 In the autumn millions of eggs were seen on the 

 trunks and branches, and an attempt was made to 

 clear them off at considerable expense, but was soon 

 given up as hopeless. It seems strange that man 

 should have to acknowledge himself defeated by any- 

 thing so fragile as a butterfly, but so it was. How- 

 ever, the birds came to the rescue. Twenty pair of 

 titmice, as well as some wrens, came and built in the 

 garden the following spring, and that summer the 

 trees suffered much less. By the year after, the plague 

 was so thoroughly under control that they remained 

 in full leaf the whole season. 



The wren, like the titmouse, is perpetually eating, 

 and feeds her young thirty-six times in an hour ; the 

 cuckoo, too, eats all day long, every five minutes or so, 

 and devours about 170 good- sized caterpillars in the 

 day ; and as each of these caterpillars, if allowed to 

 reach the butterfly state, might lay some 500 eggs, 

 every cuckoo rids us of a possible 85,000 odd cater- 

 pillars daily ! 



And the work goes on vigorously in winter, as well 

 as in spring and in summer, for, with all the vigilance 

 of the birds, caterpillars and grubs innumerable escape 



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