NESTING-HOUSES 25 



from the elements if the box is put up with the 

 entrance hole facing away from the direction 

 from which the prevailing storms come, although 

 with the kind of roof shown on page 18, this 

 matter becomes of less importance. 



Ernest Thompson Seton gives the following 

 general suggestions : " As a general principle I 

 find that the birds like a tight fit. Small birds 

 will not nest in a large hole. I find it a good 

 plan, in some cases an essential, to go around in 

 the spring and dust the nesting-houses with pow- 

 dered sulphur. They become so infested with 

 parasites that the birds cease to use them. In 

 fact I believe it a good plan to clean out the old 

 nests completely every year. As a practical de- 

 tail, I have found it worth while to have each 

 nest with a hinge door which would admit of 

 easy inspection without disturbing the inside 

 arrangements ; and second, to place none so 

 that they cannot be reached by a convenient 

 ladder." 



The chief things to be taken into account in 

 adapting a house to a particular bird are, — size 

 of house, size of entrance hole, location of the 

 house, and the kind of house preferred. The sec- 

 ond point is especially important, as the regula- 

 tion of the size of the hole allows one to keep 

 out all birds larger than the one for which the 



