Nesting Boxes on Poles.

The following are some approximate measurements for nest-boxes:—

For Titmice:

height, 11½ inches;
depth from back to front, 4½ inches;
diameter of round opening, 1¼ inches.

For birds of the size of a Starling:

height, 18½ inches;
depth back to front, 9 inches;
diameter of opening, 1¾ inches.