Specifications for a Purple Martin Birdhouse

Gourds

• A gourd needs to measure at least 8 inches in diameter and 6 inches in height. Cut an entrance hole that measures 2 1/4 inches in diameter about 3 to 5 inches above the inside floor. Drill at least four 1/4-inch holes in the bottom for drainage and at least four 1/4-inch holes around the neck for ventilation. Use light-colored paint on the outside surface area to minimize heat accumulation. Hang the gourd from a horizontal bar about 8 to 15 feet above the ground.

Martin Houses

• Most martin houses have eight to 12 compartments that can each house one pair of birds. Each compartment has to have more than one entrance, each measuring 2 to 2 1/2 inches in diameter. Place the entrances for each compartment on different sides of the birdhouse, if possible. The floor should measure at least 6 by 6 inches, and each compartment should be at least 4 inches tall. Build a porch at least as wide as the entrance hole because martins like perching outside their nests.

Choosing a Martin House

• Pet stores sell plastic gourds for convenience, but a hollowed-out gourd can work just as well. Martin houses tend to take up less space and are more secure, but they usually cost more. These birdhouses can all attract martins for years if other birds are kept away from it. Store the birdhouse inside or plug the entrances when the birds migrate away.

Considerations

• Purple Martins colonize houses as low as 6 feet above the ground but prefer houses 12 to 20 feet high. One reason is the higher the house is, the safer the birds feel from predators such as cats, raccoons, opossums, squirrels and snakes. If the house is on a pole, attach a guard cone with a radius of at least 15 inches at least seven feet above the ground. This will keep cats and squirrels from leaping up into the house and block anything from climbing up the pole.