How to Design a Martin Bird House

How to Design a Martin Bird House
Purple Martins are the largest species of swallow. They live in colonies and consume insects for food. House Sparrows and European Starlings compete with them, directly contributing to the decline of martin populations. The species fight and martins are driven from nesting spots or killed.

Infiltrating predators also cause birds to abandon their housing. Human helpers can monitor the situation and add barriers to predator invasion. Additionally, houses may be equipped with hinged compartments for removing other nesting birds.


Difficulty: Moderately Challenging

Indoor Design

Step 1
Use wood that has not been subject to chemical treatments. Use 3/4-inch wood for better insulation.

Plastic houses should block sunlight. Metal homes should have insulation added to the attic area to protect the nestlings from temperature extremes.
Step 2
Make the flooring of wood or textured material to allow the feet of nestlings to grip and catch hold. Do not use carpet or any component that retains moisture.
Step 3
Design the compartment with a minimum size of six inches for each dimension; however, as they need to fit up to eight birds and martins prefer a larger living area, a 12-inch by 7-inch by 6-inch (depth/width/height) space is preferable. Houses should offer space for at least four nesting pairs.
Step 4
Size the door to the house between 1 3/4 inches and 2 1/4 inches in diameter to allow the birds to enter, but deny other birds access. Place the entrance 1 inch to 1 1/2 inches from the floor of the house.

Crescent-shaped doors are able to block starlings. They should be placed one-half inch off the floor. Entrance openings of either type should not have perches, also to deny other bird species a way in.

Outdoor Design

Step 1
Balconies or porches are optional and controversial additions. Those opposed to them argue that they allow nestlings to wander from their compartment and rob other broods of food.

Separate broods from mingling by placing dividers between compartments on continuous porches. Set railings five-eighths of an inch or less from the balcony floor to prevent any birds from becoming trapped beneath. Construct porches with a width of 4 inches.
Step 2
Extend the roof to protect entrances from rain. The roof should also cover ventilation holes. Several drain holes should be made in the flooring of each compartment to allow water to flow out of the housing.

Protect the birds from full sun by painting the exterior white to keep the house cool (do not paint inside).
Step 3
Gourd houses should not hang in a way that allows them to swing in a full circle. If possible, they should be allowed to swing only left to right or front to back.

Gourds are a better choice to deter predators because they move freely and other bird species do not like the movement; however, they should not be allowed to bump against obstructions as they swing or the martins will abandon the nest.
Step 4
Locate the house in an open space, free of obstructions. The birds prefer to live away from the tree line and not too close to humans. The Purple Martin Conservation Association suggests a minimum of 40 feet from any trees and 100 feet from human habitation.

Tips & Warnings

Add additional perches above the houses. Old antennas make excellent perch material.

Article Written By Alice Moon

Alice Moon is a freelance writer with more than 10 years of experience. She was chosen as a Smithsonian Institute intern, working for the National Zoo in Washington, D.C., and has traveled throughout Asia. Moon holds a Bachelor of Science in political science from Ball State University.

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