BIRD ENEMIES OF FOREST INSECTS 



691 



a cicada escapes them. The exter- protection and increase of birds in the 

 mination of the insect in city parks state forests. Hundreds, yes thousands, 

 is freely predicted because of the abund- of nest boxes have been erected for the 

 ance of Enghsh sparrows in these birds; nesting sites have been carefully 

 reservations. The crow-blackbird or preserved for those birds that will not 

 grakle is another bird that pursues nest in boxes; and measures have been 

 cicadas so relentlessly that it some- adopted to help the birds through the 

 times destroys all of a brood in hardships of winter. In England the at- 

 restricted areas. traction of 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 yearly 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 saw^y. 



The method is con- 

 sidered entirely econ- 

 omical, because it is only through 

 the natural enemies that the suppression 

 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 

 are of some value in combating almost be correspondingly decreased, 

 all of the forest insects. Their great In the case of most forest insects, 



value has by no means passed unrecog- direct suppression b}- man is impossible. 



The Night H.^wk 



this bird patrols the air for insects in the late .'afternoon and night. 

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

 different kintss of bark beetles 



We have mentioned by no means all 

 of the tree pests that have important 

 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 



nized. In European countries, the aid 

 of birds has been widely invoked in 

 controlling tree insects. In those coun- 

 tries where forestry has been highly 

 developed one of its branches is the 



This makes the work of natural enemies 

 of the pests of paramount importance. 

 Among these enemies birds are the 

 most voracious, and rally the quickest 

 to the scene of an outbreak. 



