16 



Experience with nesting boxes on trees, particularly in woods, 

 has proved that they are occupied mainly by squirrels and 

 mice or remain unused. These animals, as well as cats and 



A Dorothy Perkins rose bush. Grown on a bird-house pole for 

 ornamentation and protection against cats. (After Our Dumb 

 Animals.) 



sometimes rats, drive the birds out and destroy their eggs and 

 young (see Plate V.). Nests on poles are not so often visited 

 by the foregoing enemies of birds, and such nests may be 

 protected against them by any one of the devices shown (Fig. 

 22). Nests on isolated trees may be safeguarded in a similar 



