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 ])rem- 
ises of these sparrows will find recommendations in Farmers’ Bulletiu 
493, The English Sparrow as a Pest. European starlings, wliicli at 
present are not distributed beyond a narrow strip of the Atlantic coast 
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Fig. 41 .—Lumber diagrams for martin house. Thickness of boards f 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. vSquirrels give more or less 
trouble by gnawing houses, eating eggs, and killing nestlings. Ived 
squirrels, in particular, have a very bad reputation in this respect, 
and many experimenters keep their grounds free from them. Sonie 
regard flying squirrels as but little better than red ones. Even gray 
