110 THE SAWFLY 



the summer of 1912, the larch plantations of the Manchester 

 Corporation at Thirlmere have been declared practically 

 free from sawfly pest ; the trees were green and healthy all 

 through the season, and a good growth of wood was recorded. 

 . . . Why is it that on the slopes of Skiddaw, at Winder- 

 mere, and elsewhere the pest is as bad as ever? . . . the 

 Thirlmere estates alone, so far as our information goes, show 

 a well-marked immunity.' 



Dr. Hickson attributes this immunity mainly to the 

 presence of great numbers of birds. He says that three 

 species of tits, robins, and starlings made most use of the 

 boxes. He also credits the ichneumon fly with a very 

 large share in the good work. The lesson is well worth 

 the attention, not only of foresters, but of gardeners and 

 all who depend upon growing crops subject to insect 

 visitation. Insectivorous birds are most effective police, 

 and find themselves in board ; but suitable lodging 

 must be provided for them, else they will not remain 

 on the ground in spring and early summer when the 

 output of insects is at its height. It is within the power 

 of any one who has control of even a quarter of an acre 

 of country ground to attract birds by providing facilities 

 for nesting. Rich will be the reward of him who 

 becomes the host of that rare and lovely creature the 

 pied flycatcher, which occupied ' at least one box ' in 

 the Thirlmere woods in 1912. 



So much, and it is much, for the services of soft- 

 billed birds tits, tree-creepers, warblers, etc., which 

 make their chief diet upon insects; but it would be 

 wrong to conclude that hard-billed birds grain and 

 seed-eaters bear no share in this beneficent work. 

 The inordinate and unwise excess to which pheasant 



