12 



bluebirds will not enter a hole of this size. Long axis vertical 

 (Fig. 14). Tree swallows will use this. 



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Fig. 14. — Bluebird box and details. 



Tree Sivallow. — Interior dimensions, 4j by 4j by 8 inches. 

 Entrance hole about, not over, 1^ inches. Long axis vertical. 

 Bluebirds also use this box. (See Plate L, Fig. 2.) 



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24%' 



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Fig. 15. — Flicker box and details of construction. 



This is the most popular box (with the birds) that I have 



seen. 



Starling. — This European bird will soon be common and 

 may become a pest. It requires an entrance hole about 2 inches 



