You may find out after investing money, time, and hard work, that your yard is too tree enclosed for martins, or your martin house is difficult or impossible to manage. There are many sources of information available. PMCA members can benefit from all the current information published in the colorful Purple Martin Update magazine. Choose the right location. One of the major reasons people fail to attract martins is that they place the martin housing incorrectly.
Martins have very specific space requirements.
Their housing should be in the center of the largest open spot available, about 30-120 feet from human housing. There should be no trees within 40 feet, preferably 60 feet. In the southern half of their breeding range, martins are less fussy about house placement, so sometimes housing can be within 25 feet of trees and still attract martins. But the farther housing is placed from trees, the better. Housing height should be about 10-15 feet.