BIRD HOUSES AND HOW TO BUILD THEM. 



15 



ENEMIES OF HOUSE BIRDS. 



Birds have numerous enemies from which a careful landlord will 

 try to guard them. Among these is the English sparrow, whose per- 

 sistent attacks too often drive more desirable birds away from their 

 nests and from the neighborhood. Those who wish to free their prem- 

 ises of these sparrows will find recommendations in Farmers' Bulletin 

 493, The English Sparrow as a Pest. European starlings, which at 

 present are not distributed beyond a narrow strip of the Atlantic coast 



2/' 



27" 



/77-/ 



30' 



3O' 



FIG. 41. Lumber diagrams for martin house. Thickness of boards \ inch. 



region centering about New York, are to be condemned for their 

 pernicious interference with native house birds. 



Cats and large snakes are enemies of birds, the former perhaps 

 killing more birds than any other mammal. Trees and poles support- 

 ing houses should be sheathed with tin or galvanized iron to prevent 

 these enemies from climbing to the nests. Squirrels give more or less 

 trouble by gnawing houses, eating eggs, and killing nestlings. Red 

 squirrels, in particular, have a very bad reputation in this respect, 

 and many experimenters keep their grounds free from them. Some 

 regard flying squirrels as but little better than red ones. Even gray 



