A vital key to getting Purple Martins to select your site is LOCATION.These are some basic parameters that you can use as a guide.
Remember to be realistic about the locations you have in mind to place a martin house. Keep in mind that if you have a Homeowners Association, it may be more difficult for you. You may have to check with your HOA to see if having a purple martin bird house is allowed.
Ask yourself, Where is the most open area on your property? Sometimes a backyard may NOT be the most purple martin friendly habitat. Would you consider placing the housing on your front lawn?
(Though there are many exceptions in real life.)
1. Housing should be at LEAST 40 feet from trees...preferably more, though in the 'South' it is said that Martins are not as preoccupied with this.
2. Housing should be no further than 120 feet from your home. And as close as 30 feet. My philosophy is keep it on the closer side. You will enjoy your purple martins more and they actually benefit from the added protection we provide.
3. The house itself should be AT LEAST 10 feet up in the air. Preferably 15 feet. Though once established, within a colony, purple martins will tolerate lower heights.
4.Keep shrubbery away from the bottom of housing.