BIRD ENEMIES OF FOREST INSECTS 



691 



a cicada escapes them. The exter- 

 mination of the insect in city parks 

 is freely predicted because of the abund- 

 ance of English sparrows in these 

 reservations. The crow-blackbird or 

 grakle is another bird that pursues 

 cicadas so relentlessly that it some- 

 times destroys all of a brood in 

 restricted areas. 



protection and increase of birds in the 

 state forests. Hundreds, yes thousands, 

 of nest boxes have been erected for the 

 birds; nesting sites have been carefully 

 preserved for those birds that will not 

 nest in boxes; and measures have been 

 adopted to help the birds through the 

 hardships of winter. In England the at- 

 traction cf birds by supplying a large 

 number of nest boxes 

 was adopted as a def- 

 inite method of com- 

 bating the larch sawfly . 

 The boxes were 

 made of waste lumber 

 slab wood at a low 

 cost. "In the first 

 year (1908,) sixty 

 boxes were distributed 

 and 31 per cent were 

 occupied. The num- 

 ber of boxes was in- 

 creased yearlv until in 

 1911 there were 347 

 boxes of which 66 per 

 cent were occupied." 

 In 1913 about 75 per 

 cent of the boxes had 

 tenants. In addition 

 to the provision of 

 nesting boxes, feeding 

 stations were erected 

 for the purpose of 

 holding the birds in 

 the region during the 

 winter. The result 

 was a material in- 

 crease in the number 

 of birds resident in 

 the forests attacked 

 by the sawfly. 



The method is con- 

 sidered entirely econ- 

 We have mentioned by no means all omical, because it is only through 

 of the tree pests that have important the natural enemies that the suppression 



The Xight Hawk 



this bird patrols the air for insects ix the late afternoon and night, 

 it destroys many forest pests and is known to feed upon eighteen 

 different kinds of bark beetles 



bird enemies, but enough has been 

 recorded to indicate that birds are the 

 most important natural enemies of 

 certain of these pests, and that they 

 are of some value in combating almost 

 all of the forest insects. Their great 



of the pest can be expected and if these 

 enemies are increased in number, the 

 outbreak will subside much sooner than 

 otherwise, and the pecuniary loss will 

 be correspondingly decreased. 



In the case of most forest insects. 



value has by no means passed unrecog- direct suppression by man is impossible, 



nized. In European countries, the aid This makes the work of natural enemies 



of birds has been widely invoked in of the pests of paramount importance, 



controlling tree insects. In those coun- Among these enemies birds are the 



tries where forestry has been highly most voracious, and rally the quickest 



developed one of its branches is the to the scene of an outbreak. 



