align="right">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

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.