Birds of Oregon and Washington 247 



Superintendent of Nature Study in the public 

 schools of St. Paul, Minnesota. 



Boxes are best when made out of sections of 

 hollow trees, or limbs, the holes having a dia- 

 meter of from three to eight inches. 



Boxes made of slab-wood are next in value. 

 The bark on the boxes seems to induce the birds 

 to undertake housekeeping when plain boards 

 do not . But the bark should never be nailed on 

 boards, because in the heat and rain, it warps, 

 and vermin swarm beneath it. A fir-bark roof, 

 projecting on each side, may, however, be put 

 upon a box with advantage, the curve in the 

 bark gives ventilation, which should be provided 

 in the tops of all bird-houses. 



Next to slab-wood, unplaned or rough-sawed 

 boards are best. If planed boards must be used, 

 rub them with moist earth, or, if the boxes are 

 to be used in trees bearing leaves, they may be 

 painted green. 



The boxes should be made of different sizes, 

 adapted to the several kinds of birds for which 

 they are constructed. For Wrens, let the box 

 be 7 x 5 x 5 inches on the inside, with a hole, a 

 very little larger than a twenty-five-cent piece, 



