Note that the plan calls for nailing a 3/4-inch strip onto the boards which are the ends of the house. his makes the 11 1/2-inch board the full 12 1/4 inches necessary to make the rooms 6 x 6 inches. Any less space per room will discourage martins and encourage sparrows.

Watch where you place your nails, because you will want to saw the dados (grooves) and roof pitch after the strips are added. Because of its nail-holding ability, solid lumber rather than plywood works best for the ends. Drive l-inch nails on either side of the room dividers to hold them in place. Leave the brads extended 1/4 inch above and below the ceiling/floor panel. If you don’t have a table saw to make the dado cuts, you can nail two 1/2-23/4-inch strips of 1/4-inch plywood to the inside ends to form the grooves. In this plan, a l-inch space is allowed in the attic for insulation.

A l-inch Styrofoam panel provides superior insulation, but a few sheets of newspaper sandwiched between sheets of corrugated cardboard works well, too. The vent holes in the ends can be 3/8-5/8 inch in diameter. Note that the front pieces are cut 1/4 inch short in height. This, too, allows for attic ventilation and makes it possible to remove these fronts to clean the boxes. Use a 3/8-inch dowel for the roof perch. You may shingle the roof, but this is not necessary. Paint the entire house white.

Do not stain or paint the house dark colors. Holes should be at least 2 inches in diameter; 2 1 /4 1/2 inches is recommended. Rectangular holes 2 x 3 inches (high) are also suitable.

Just follow these instructions for bird house patterns & you’ll have no trouble

Installation

Erect the house on a pole or pipe 12 to 18 feet high in an open area away from trees. This house is light enough to mount on telescoping poles which are commercially available. This facilitates cleaning. Have your martin house erected by April 15 and preferably by March 25. Holes may be blocked with strips of wood in the fall and winter to keep out starlings and sparrows. Clean out old nests in September. You may want to locate it close by any style of unique bird feeders that you may have installed.

Biology

Martins usually lay four or five eggs. Incubation is about two weeks, and age to first flight is about four weeks. Martins build only one nest per year, but they may renest if the first attempt is an early failure. After flight, martins will return to the house for about two weeks to roost and perch. Martins feed on the wing and eat a variety of flying insects, including flies, beetles, moths and cicadas. They will not kill bee hives. Scouts-mature males-may arrive in late March. After aggregating in large flocks in late summer, they depart for wintering grounds in South America during late August and early September.

Comment

Martins are sometimes difficult to attract, but it’s easier if you have some well constructed purple martin bird houses in place. Well-shaded lawns with big trees are poor habitats. It may take a year or two to attract martins to a new house; don’t get discouraged. If after two years you are still unsuccessful, try moving the house to a different location-sometimes 25 feet can make a difference. Don’t expect a nest in every room. Four nesting pairs in a 12-room house is good occupancy. Any additional rooms are used for roosting and for young, preflight birds. Also, sparrows will likely fill a few empty spaces. Before the martins are nesting, leave the sparrow nests alone to avoid disturbing the martins.

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