34 OUR NATIVE BIRDS 



have to take newly sawed lumber, rub the boards with 

 moist earth. Limbs and trunks may, of course, be bored 

 out, or they may be ripped first, then a cavity cut out, 

 and the two halves screwed together again, but these 

 boxes are likely to open along the joints unless very 

 carefully made. Do not nail false bark on the boxes ; 

 it is never quite tight and only harbors bird parasites. 

 It is, however, advisable to fasten the bark on summer 

 cut wood with small nails. On wood that was cut in 

 late autumn or in winter, the bark adheres naturally. 

 The wood of rough-barked deciduous trees is best for 

 bird boxes, but any kind of wood may be used. 



The width of the entrance hole, the location of the 

 box, and its height from the ground must receive 

 careful attention. Birds do not like to approach their 

 nests over wide open spaces. The old nesting material 

 should not be removed from the boxes, the birds will 

 attend to that themselves. The boxes must not be 

 exposed to the noon and afternoon sun, and small 

 openings should be left between top and cover to 

 secure ventilation. 



It is absolutely necessary to fasten the boxes well. 

 If they are shaky and are rattled by the wind, or if 

 branches and twigs strike against them, the birds will 

 not use them. The fastening may be done by means 

 of strong wires, nails, or screws, the method depending 

 somewhat on the value of the tree to which the box 

 is to be fastened. 



Some of the best European observers advocate sur- 

 rounding the boxes of titmice and wrens with thorns. 



