17 



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coarse sawdust and dry earth mixed must be placed in the bot- 

 tom, as woodpeckers make no nest but rely on decaying wood 

 or chips which they strike oft' the tree 

 to make a bed for their eggs. (See 

 Figs. 16 and 17 and Plate V.) 



A Warning. — It is best to have 

 all deep nesting boxes roughened in- 

 side. They should be either rough- 

 sawed or scored in some way so that 

 small birds like tree swallows may get 

 out if they once get 

 in. If a box is planed 

 inside and is not large 

 enough in diameter 

 for them to fly out 

 freely they cannot 

 climb out. This is 

 why many have been 

 found dead in such 

 boxes, and why blue- 

 birds cannot escape 

 from water conduc- 

 tors when they get 

 inside and are some- 

 times found drowned 

 in cisterns. 



Sparrow Hawk. — 

 Flicker boxes have been used occasionally by sparrow hawks, but 



a more roomy box, at least 8 inches in 



diameter, would be better. 



Screech Old. — Inside dimensions of box 



actually occupied on my place in which 



young were raised, 7 by 11 by 15 inches. 



Long axis vertical. Size of entrance hole, 



3 inches wide by 4 inches high (Fig. 



18). 



Wood Duck. — Inside measurements, 

 Fig. 18. -Owl box. ^^^^^^ jq ^^ ^^ ^^ 24 inchcs. Entrance, 



4 inches in diameter and 18 inches from the bottom. Long 

 axis vertical. 



& 





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Fig. 17. — Flicker box and details. 

 Survey.) 



(After Biological 



