8 



Many people wish to rid their premises of sparrows or to 

 drive them out of bird houses, but not to kill them. It is 

 practically impossible to drive them from any premises without 

 continuous persecution, but they may be evicted from bird 

 houses by systematic work without killing any. Various plans 

 have been recommended, such as putting up nesting boxes 

 without perches or with entrance holes in the bottom, providing 

 a great plethora of nesting boxes, or suspending them by wires. 

 None of these expedients is of any permanent value except 

 possibly the last, and that has not been uniformly successful. 



Fig. 1. — Perspective and sectional drawings of an 

 improvised nest box for the interior of build- 

 ings. (After Biological Survey.) 



Fig. 2. — Nest box opening at 

 the top. (After Biological 

 Survey.) 



Where this happens the boxes intended for native birds may 

 be so arranged that the sparrows may be kept out, entrapped 

 or driven out. A box having an entrance not over seven- 

 eighths of an inch in diameter will admit house wrens and keep 

 out sparrows; chickadees have been known very rarely to 

 nest in a box with a round entrance one inch in diameter, and 

 this usually keeps out sparrows, but if the entrance is large 

 enough for any bird larger than the house wren the sparrow 

 may get in. As sparrows begin nesting earlier in the spring 

 than most other birds they may be driven from a nesting box 



