Albert Frederick Siepert, Bird Houses Boys Can Build
“ CONSTRUCTION OF BIRD HOUSES.Bird houses may be divided into three main classes: (1) those made of sawed lumber to specified dimensions; (2) the rustic type made of (a) slabs of wood with the bark left on, or (b) pieces of tree trunk, or (c) of sawed lumber trimmed with bark or twigs; and (3) cement or stucco houses. In each case the entrance should slant slightly upward to keep the rain out. FIG. 10. WREN HOUSES.Almost any sort of lumber may be used, but birds take most readily to that which has been weathered out of doors. ”
