is upon us, which means neighbors will soon be arriving from the
south. These “neighbors” are Neotropical migrant birds who
typically winter in Central and South America before returning
in mid-February to Oklahoma for the summer months. One of the
loveliest Neotropical migrants is the purple martin. With a
little planning and effort, Okie residents can make sure these
colorful neighbors enjoy the area enough to stay long-term—by
building a purple martin house.
Martins are members of the swallow family that nest in colonies often near human buildings. Since martins like people, it is safe to place houses close to human activity. Martins feed on insects, so they need a clear view of open space in which to feed. Keep houses at least 40 feet away from buildings, trees and other obstructions. Houses should be placed between 12 to 14 feet off the ground.
American Indians used to attract purple martins to their villages by hanging gourds. All these years later, gourds are still a great way to provide shelter for martins. Well-maintained gourds can last up to 30 years. To prepare gourds, soak them for 15 minutes in a copper sulfate solution (one pound copper sulfate dissolved in five gallons of water). After they are dried, paint them with white oil-based paint to minimize heat. The entrance hole should be 2-1/4 inches in diameter, and three to six quarter-inch drainage holes should be drilled into the bottom.
Houses made from PVC pipe material and masonite also are available. PVC structures are inexpensive to construct and very durable but can be difficult to clean. Wood houses should be 1/2-inch to 3/4-inch thick to insulate against heat and cold.
Several boxes may be set up in the same yard. When "fully" occupied, a house will have a percentage of compartments vacant. The occupancy rate can be increased by using porch dividers between "apartments."
Martin houses should maintain a relatively cool temperature. Since martins prefer to nest in open areas where they are exposed to direct sunlight, painting houses white to reflect heat and providing proper ventilation will help prevent excessive heat build-up. Ventilation is also important, so make sure the structure has small holes drilled in each compartment.
It sometimes takes several years to attract martins to a new site. If the house is not used in the spring, just leave it up until after fall migration. Young birds may discover it as they head south. And once they discover it, more martins will follow. With just a little work, your own home will soon be part of a thriving community of lovely purple martins.