The table given on page 16 states the height from the ground that different species of birds seem to prefer for their nests, to which several suggestions may be added. The houses should be so located that cats and other bird enemies do not have easy access to them. The openings ought to be turned away from the directions from which storms and winds most often come; and the house must hang or tilt so rain does not run in at the entrance. Such birds as the woodpeckers spend most of their time in the trees and so do not take as readily to a house set on a pole out in the open as martins or bluebirds. Flickers are seen on the ground a good share of the time in search of their favorite food, and so will frequently live in houses nailed to fence posts. Houses are more apt to be occupied if placed in position in fall or winter before the spring migration, especially houses made of freshly dressed or newly painted wood. However, such birds as the robin and bluebird rear more than one brood each season and so a house set up in May or June may have a tenant. Figs. 40 to 44 show boys of the University of Wisconsin High School placing some of the houses they had made.

FIG. 41. (PLACING HOUSES) FIG. 41.

FIG. 42. (PLACING HOUSES) FIG. 42.

FIG. 43. (PLACING HOUSES) FIG. 43.

FIG. 44. (PLACING HOUSES) FIG. 44.