Martin Houses

Not too long ago, every farmhouse had boxes, gourds or other housing to attract purple martins. Martin houses are not as common today as they once were, but with increasing interest in our environment and nonchemical pest control, the martin is regaining popularity. In fact, more people provide housing today for the purple martin than for any other bird.

The martin is not a year-round bird in Georgia; it winters in South America. Generally, it arrives in southern Georgia in early February, reaches northern Georgia by mid-March or April, then leaves during the fall.

Old martins tend to return to their old nesting areas; young birds seek new ones. This means that once a house is used, it probably will continue to be used, and new houses will eventually be occupied as first-year martins look for places to nest.

Martins make nests from twigs, weeds, dead leaves, coarse grasses and similar materials. The female lays three to eight white eggs and incubates them about 13 days. Both parents feed and care for the young. Young birds stay in the nest three to four weeks. Even after they leave the nest, young martins often return to the vicinity for a week to 10 days before final departure.

Martins will nest in a variety of houses. In the past, it was common to see a number of gourds hanging from a pole with crossarms or from a wagon wheel mounted on a post.

Unfortunately, natural gourds are not as common as they once were, and gourd houses are seldom seen today. However, you can buy plastic gourds and duplicate the older-style houses. Another possibility is to cluster jugs or manmade houses on wagon wheels or poles with crossarms.

Perhaps the most common accommodation for martins is the apartment house. You can buy wooden or aluminum houses at hardware and feed and seed stores or you can make your own.

To make your own "high rise," start with one layer, then add others as your colony grows. Generally, it is best not to put more than 24 nesting compartments in a single apartment house.

Use as light a material as you can to build your house because you'll want to take it up and down for cleaning and storing. Make compartments approximately 6 inches cubed.

Entry holes should be 2.5 inches in diameter, 1 inch above the bottom of the nesting compartment. Except for the lower layer, the center nesting compartment does not have a floor. This gives a central air passage for ventilation.

To provide good circulation, drill 5/16-inch diameter holes through the interior walls of each compartment. Drill 1-inch holes through the exterior walls of the roof section too. Be sure to screen these roof holes to keep out starlings and sparrows. Also, leave a 6" x 6" hole in the floor of the roof section. This lets air move up the central passage into the roof, then out the roof ventilation holes. Join the roof section and layers with hooks and eyes.

Paint the house inside and out with white paint. White outside helps keep the house cool. White inside helps prevent starlings from using the house. Starlings prefer a dark cavity; martins will use a light one.

If starlings and sparrows do use your martin houses, take the houses down and destroy the nests. Should cats or other climbing predators become a problem, put a predator guard on the post.

In general, martins prefer houses in relatively open areas. If possible, never put a martin house closer than 30 feet to a tree. Also remember that martins are colonial birds and like to nest together. Widely scattered houses built for solitary pairs of birds are usually unsuccessful.

Because martins love to socialize on telephone and electric wires, put their houses near utility lines if possible. Putting houses near open water is often helpful too.

Because martins feed almost exclusively on flying insects, open fields are a powerful attraction. After all, insects are easier to catch in a field than in trees. Keep martin houses away from bee yards. Martins eat honeybees.

Before you start to put martin houses up, place a pinch of sulfur dust in each nesting compartment. This helps control mites.

Put houses on poles 15 to 30 feet tall unless the area has heavy vegetation. A good rule of thumb is the lower the vegetation, the lower the pole can be. If possible, make the pole so you can take the house down for cleaning in fall and storage in winter.

If you decide to permanently install you martin houses, be sure you have some way to clean out nest compartments. For example, put the house so you can climb up on a tall ladder and use a wire hook to pull out old nest material. Also, put plugs in entry holes to keep out starlings and sparrows during winter.

Although martins feed on flying insects, their ability to control mosquitoes has been overrated. Mosquitoes actually provide a very small part of the martin's food.

Studies indicate martins seek food just after dawn until just after dusk. Most mosquitoes, however, are active at twilight or night and spend most of the day on the ground or in vegetation near the ground. So, the only time mosquitoes are available for martins is a very short period between sunrise and sunset, and then only if the birds are feeding near the ground. Thus it appears the martin plays a very small part in controlling mosquitoes.

Martins, however, do eat butterflies, grasshoppers, houseflies, deer- and horseflies, and dragon- and damselflies, so we do have reason to encourage them for insect control.

Information on purple martins and mosquito control came largely from a paper by Herbert W. Kale II, The Relationship of Purple Martins to Mosquito Control (Auk. 85:654-661, 1968).

Thanks are due to members of the Extension Forestry Department and the Institute of Natural Resources for their comments and suggestions.

Appreciation is also expressed to Mrs. Deborah Pullin, editor of Farmers and Consumers Market Bulletin, for permission to use this material, much of which appeared in the March 28 and April 4, 1973, issues.

For additional information on attracting martins and other birds, ask you county Extension agent for Bulletin 727, Attracting Birds to Your Home.

The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service, the University of Georgia College of Agricultural and Environmental Sciences offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.

An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, The University of Georgia College of Agricultural and Environmental Sciences and the U.S. Department of Agriculture cooperating. Gale A. Buchanan, Dean and Director