THE HEART OF THE COPSE 129 



pest no birds seem to deal effectually ; the only real check is 

 a few sharp showers in May, which drown the little caterpillars 

 in their tents of rolled leaves. Tits, chaffinches, chiffchaffs, 

 willow-wrens and many other birds are prompter in dealing 

 with plagues of geometer caterpillars, which sometimes attack 

 trees in much the same way. The game is larger, and pre- 

 sumably better worth catching ; and an infested copse is 

 often alive with a diverse throng of birds picking off the cater- 

 pillars from the leaves, and diving through the air at them as 

 they hang on their oscillating threads. On a breezy day the 

 air below the trees is full of small caterpillars dangling in the 

 wind. They have the power of returning on their own 

 threads, packing them up between their forefeet as they 

 climb. But the ascent is very long and laborious, and when 

 once the tits and chaffinches have been spurred on to cater- 

 pillar hunting by the sight of plenty, there are very few which 

 ever regain the boughs. 



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