The following table, copied from Farmers Bulletin, No. 609, U. S. Dept. of Agriculture, gives in small space valuable information about dimensions that experience and investigation have indicated as good for particular varieties of birds. This list includes many varieties that do not commonly live in houses built for them, however. As time goes on, we may expect to find more of these birds living in our nesting boxes because they are apt to seek the same sort of home as the one in which they were reared. The table is given to be of service to those wishing to plan new houses not shown here.
Dimensions of nesting boxes for various species of birds.
| Species. | Floor of cavity. | Depth of cavity. | Entrance above floor. | Diameter of entrance. | Height above ground. |
| Inches. | Inches. | Inches. | Inches. | Feet. | |
| Bluebird | 5 by 5 | 8 | 6 | 1-1/2 | 5 to 10 |
| Robin | 6 by 8 | 8 | [1] | [1] | 6 to 15 |
| Chickadee | 4 by 4 | 8 to 10 | 8 | 1-1/8 | 6 to 15 |
| Tufted titmouse | 4 by 4 | 8 to 10 | 8 | 1-1/4 | 6 to 15 |
| White-breasted nuthatch | 4 by 4 | 8 to 10 | 8 | 1-1/4 | 12 to 20 |
| House wren | 4 by 4 | 6 to 8 | 1 to 6 | 7/8 | 6 to 10 |
| Bewick wren | 4 by 4 | 6 to 8 | 1 to 6 | 1 | 6 to 10 |
| Carolina wren | 4 by 4 | 6 to 8 | 1 to 6 | 1-1/8 | 6 to 10 |
| Dipper | 6 by 6 | 6 | 1 | 3 | 1 to 3 |
| Violet-green swallow | 5 by 5 | 6 | 1 to 6 | 1-1/2 | 10 to 15 |
| Tree swallow | 5 by 5 | 6 | 1 to 6 | 1-1/2 | 10 to 15 |
| Barn swallow | 6 by 6 | 6 | [1] | [1] | 8 to 12 |
| Martin | 6 by 6 | 6 | 1 | 2-1/2 | 15 to 20 |
| Song sparrow | 6 by 6 | 6 | [2] | [2] | 1 to 3 |
| House finch | 6 by 6 | 6 | 4 | 2 | 8 to 12 |
| Phoebe | 6 by 6 | 6 | [1] | [1] | 8 to 12 |
| Crested flycatcher | 6 by 6 | 8 to 10 | 8 | 2 | 8 to 20 |
| Flicker | 7 by 7 | 16 to 18 | 16 | 2-1/2 | 6 to 20 |
| Red-headed woodpecker | 6 by 6 | 12 to 15 | 12 | 2 | 12 to 20 |
| Golden-fronted woodpecker | 6 by 6 | 12 to 15 | 12 | 2 | 12 to 20 |
| Hairy woodpecker | 6 by 6 | 12 to 15 | 12 | 1-1/2 | 12 to 20 |
| Downy woodpecker | 4 by 4 | 8 to 10 | 8 | 1-1/4 | 6 to 20 |
| Screech owl | 8 by 8 | 12 to 15 | 12 | 3 | 10 to 30 |
| Sparrow hawk | 8 by 8 | 12 to 15 | 12 | 3 | 10 to 30 |
| Saw-whet owl | 6 by 6 | 10 to 12 | 10 | 2-1/2 | 12 to 20 |
| Barn owl | 10 by 18 | 15 to 18 | 4 | 6 | 12 to 18 |
| Wood duck | 10 by 18 | 10 to 15 | 3 | 6 | 4 to 20 |
[1] One or more sides open.
[2] All sides open.
HOUSES OF SAWED LUMBER.
The boy with an outfit of tools at home, or with a teacher of manual training interested in birds, can make all of the houses to be described in this section. Figs. [10] and [11] show simple houses for wrens and bluebirds. Drawings for this type of house are shown in Figs. [14], [15] and [21]. While the surfaces of lumber used for these houses may or may not be planed, care must be taken that all pieces are sawed or planed to the correct sizes with edges and ends square and true so there will be no bad cracks for drafts and rain to enter. Be careful to nail the pieces together so that they will not have occasion to crack or warp. A good way to save time and lumber is to prepare a piece of stock, getting it of the right thickness, width and length, and then to saw up this stock on lines carefully laid out as shown in the drawings of the bluebird and wren houses, flicker nest, robin shelf and finch house. The most difficult houses to build are those for martins. In Fig. [45] is given a drawing for a small home arranged to care for eight families, while the photographs, Figs. [8], [9,] [38], [66] and [67] show larger, finer and more difficult houses. The doors or openings are 2-1/2" in diameter and can be made with an expansion bit or a key-hole saw. All of these houses are to be made so they may be cleaned. Sometimes the bottom is hinged on two screws or nails, and held in proper place by a dowel (bluebird house, Fig. [21]); or screwed in place (wren house, Fig. [21,] and martin house, Fig. [45]); or hinged and held in place by a brass spring (wren house, Fig. [14]).
FIG. 11. HOUSES FOR WRENS AND BLUEBIRDS.