How to Build a Multi-Bird House
Decorative and functional, a multi-tenant birdhouse attracts birds that nest in small colonies, including the purple martin. Voracious insect eaters, purple martins are welcomed visitors to yards and gardens where they capture their prey on the wing, but they are selective in choosing their nesting sites. To increase the success of attracting breeding pairs of purple martins, the Cornell Lab of Ornithology recommends building a multi-bird house to the proper specifications and then placing it in a suitable location. Once a nesting area is established, purple martins return to the same sites year after year. For a modular birdhouse, each module is a separate level consisting of six individual nesting compartments, and each compartment is 7 inches wide by 7 1/8 inches deep and 7 1/2 inches high. Stacking multiple modules increases the number of available nesting boxes.
Lay out three crescent-shaped entrance holes on each of the longer side pieces, centering the first entrance in the middle of the board and then, spacing evenly, another entrance hole on each side. According to the Purple Martin Conservation Association, a crescent-shaped entrance hole measuring 3 1/2 inches wide by 1 1/2 inches high discourages starlings from entering. Cut out the openings with a jigsaw.
Lay out two of the longer side pieces with two of the shorter end pieces to form a 24 inch wide by 16 inch deep rectangular frame. Use weather-resistant nails to attach the pine boards, driving three nails through the ends of each side section.
Measure and mark the position for the main plywood divider, centering it along the length of the frame. Measure and mark the positions for each of the four shorter dividers, creating six evenly spaced nesting compartments. Nail the dividers in place.
Center the completed frame on the plywood floor section, and then center the plywood roof on top. Nail the sections together, forming the first completed level of the multi-bird house.
Add additional levels as desired, repeating the process for building each frame and inserting the dividers to create the nesting compartments.
Paint the completed birdhouse with white, exterior grade paint. According to the Purple Martin Conservation Association, the white coloring helps to attract purple martins. The light colored paint also reflects the heat from sun, helping to keep the nesting areas cooler.
Things You Will Need
- Saw (power or table)
- Exterior grade plywood, 3/8 inches thick
- Pine boards, 7 1/2 inches wide
- Hammer or pneumatic nail gun
- Weather-resistant nails
- Birdhouse Parts:
- 1 Plywood roof section, 26 inches long by 18 inches wide
- 1 Plywood base section, 26 inches long by 18 inches wide
- 2 Pine Side sections, 24 inches long by 7 1/2 inches wide
- 2 Pine End sections, 14 1/2 inches long by 7 1/2 inches wide
- 1 Plywood Main divider piece, 22 1/2 inches long by 7 1/2 inches wide
- 4 Plywood Short divider pieces, 7 1/8 inches long by 7 1/2 inches wide
- Mount the purple martin birdhouse on a pole 10 to 20 feet high and at least 40 feet away from trees and buildings.
- Adding hinges to each level allows access for cleaning the nesting compartments.
- Remove starling and sparrow nests. These aggressive birds establish their territories and nests early in the breeding season, before the purple martins migrate north.