ome large residence or public building. Figs. 20 and 37 show houses
made of a section of a tree split or sawed in halves, the nest cavity
hollowed out, and then fastened together again with screws. The top
should be covered with a board or piece of tin to keep out rain. The
third division of this type of house is made of sawed lumber and then
trimmed with bark or twigs. In this way the same frames may be made to
appear as very different bird houses when completed. Such houses are
shown in Figs. 30 to 34. Sometimes a pail is used for the frame and
then covered with bark, as the center house of Fig. 28. This house has
a partition placed half-way up making it a two family apartment, and
is provided with ventilating and cleaning devices.

CEMENT AND STUCCO HOUSES.

Houses may be cast of concrete as Fig. 39. This requires a mold or
form, and takes considerable planning to insure success. A form is
made whose inside dimensions are those of the outside of the bird
house, and of the desired shape. A second form, or core, to be placed
inside of the first form, is made as large as the inside of the bird
house. The two forms must be mounted so they will remain in the right
relation while concrete is placed in the space between them. After
this has set, the forms may be removed, cleaned and used again. The
roof is generally made separately and put in position last. Or the
roof can be cast as a part of the house in which case the bottom is
inserted last. Birds do not take as kindly to this type of house as a
rule, as to those made of wood.

[Illustration: FIG. 13. STUCCO HOUSE FOR MARTINS.]

The stucco house has many possibilities. Fig. 38, shows a group of
such houses designed to match the general appearance of garages in
good residence districts. The frame is made of wood and the stucco
applied by one of the methods in use on large houses. Seventh grade
boys have made such houses, using 3/8" material for the frames,
tacking on wire netting and then plastering each side of the house in
turn with concrete. The sides were given a pebble-dash surface, while
the roof was finished with a steel trowel to give a smooth surface
that will shed water readily, Fig. 13.

[Illustration: FIG. 14. (WREN HOUSE)]

[Illustration: FIG. 15. (WREN HOUSE)]

A CAREFULLY PLANNED PROJECT IS SHOWN IN VARIOUS STAGES OF COMPLETION
IN FIGS. 15-19.

[Illustration: FIG. 16. WREN HOUSE.]

[Illustration: FIG. 17. ECONOMY OF TIME AND MATERIAL WHEN LAID