NESTING-BOXES 239 



which they can be nailed or screwed up; and still 

 others are suspended so as to swing in the wind. 



When houses are put up on posts, the posts may 

 be jointed near the ground so that they can easily be 

 taken down. This may be done by setting into the 

 ground a short post projecting a few feet above the 

 surface, and fastening to this the post on which 

 the box is placed. The two posts may be fastened 

 together by means of a large hinge and clasp, or by 

 joining the two posts by two long bolts. When it 

 is desired to take down the house, one bolt may 

 be removed and the post rotated around the other. 

 If the house is heavy, as for the martins, two posts 

 may be driven into the ground and the other post 

 fastened between them. 



Protection from the cat. Two enemies of our 

 native birds are unfortunately very common, the 

 cat and the English sparrow. The birds can be pro- 

 tected from the cat to some extent, in the construc- 

 tion of the house, if this is made deep with the 

 entrance hole placed near the top and with the roof 

 projecting well out over the entrance. Still further 

 protection may be given after the house is put up. 

 A piece of zinc or tin about two feet wide may be 

 wrapped around the tree or post below the box and 

 fastened at such a height that the cat cannot leap 

 above it from the ground. It is unable to climb over 

 this. If boxes are placed on slippery poles, cats 

 seldom climb them. A method used on the Ford 



