NESTING-BOXES 233 



is impossible to make any definite statement re- 

 garding this matter till a large number of experi- 

 ments have been tried. 



The following table shows the number of houses 

 occupied on the author's place of about three acres, 

 situated on the edge of a small city : — 



Size and shape of house. The size of the house 

 depends on the size of the nest made by the birds. 

 The bottom of the box should be just large enough 

 to accommodate the nest usually built by the bird. 

 In the case of woodpeckers, which make no nests, 

 the size of the house depends on the size of the bird. 



A great variety of shapes may be employed. Some 

 boxes have the long axis vertical, some horizontal, 

 and others are nearly cubical in shape. Probably no 

 one shape is best for all birds, but the box with the 

 long axis vertical has one advantage, that it can be 

 made practically cat-proof if it is built very deep, 



