Although there is no guarantee that Purple Martins can be attracted to any specific location, there are factors that increase the chances of success.
Offer housing with multiple compartments
Purple Martins prefer to live in groups. Appropriate housing for them is available in a wide variety of styles and configurations. Both houses and gourds (natural or manufactured) can attract Purple Martins. Many landlords offer both by attaching gourds to a traditional Martin house.
Purple Martins won’t nest where predators can hide. Housing should be located at least 20 to 30 feet from any trees or other obstructions (excluding human houses) which are taller than the martin house.
Place the housing near water
Martins prefer to nest near water. A location near a natural body of water, either fresh or saltwater, or even an unenclosed swimming pool, increases the chances of attracting birds.
The first year a house is put up it will probably attract the youngest birds – those which hatched the prior year. With the incoming migration, the older and more experienced Martins arrive first with progressively younger birds arriving up to some weeks later. The youngest birds, the prior year’s hatchlings (referred to as second-year or “SY”) can arrive up to a month later, so don’t give up.
Play a tape of Purple Martin songs
Once a Purple Martin arrives at a possible nesting site, it calls to attract other Martins to form a colony. Males are especially interested in attracting desirable females. Playing recorded Purple Martin songs particularly the “Dawn Song” early in the morning, can also attract Martins to check out your housing, although it may not guarantee they will remain and nest.
Keep the “bad guys” away
Competitors can drive Purple Martins away and destroy their colonies. Once the housing is placed in the right location, the owner must also insure that other birds do not establish residence before Purple Martins can occupy the compartments. Starlings and House Sparrows are the most common problem pests. Both these species are non-native, non-protected birds that should be eliminated from the site. Not only will they prevent Purple Martins from nesting, but they will also destroy the eggs and young in Martin nests. An owner must be prepared to eliminate these pests or should not put up martin housing since it will do more harm than good.
Give the nests a head start
Purple Martins like cavities with nests inside. Placing some nesting material like coconut fiber, pine needles, or wood shavings in the compartments will help attract and retain the martins and will also save energy which the birds would otherwise expend in nest building.Prospective landlords who are encountering difficulty attracting or keeping Purple Martins at their site may wish to refer to the following articles from the Purple Martin Conservation Association: 10 Reasons Why People Fail to Attract Purple Martins 12 Reasons Why People Lose Their Purple Martins