The major reason people fail to attract martins is that they place their martin
housing incorrectly, or their site is inappropriate martin habitat to begin with.
Martins have very specific aerial space requirements (what most people refer to
as the "Glide Path" or "Swoop Path").  Housing needs to be placed in the
center of the most open spot available and 30-150 feet from human housing or
areas where people gather on a regular basis.  Within 40 feet (but preferably 60
feet), there should be no trees or buildings taller than the martin house.  But,
the general rule is, the farther the housing is placed from trees, the better.  In
the southern half of their breeding range (Texas over to Florida), martins are a
little less particular about housing placement.  Southern landlords can often
place houses within 15-20 feet of a tall tree (as long as all other sides have
more clearance) and still attract martins.  Height of the housing can be no
lower than 10 feet.  Keep tall bushes, shrubs and vines at least 6 feet away
from the pole.  Do not attach wires to a purple martin house, especially if they
lead to trees, buildings, or to the ground (this gives predators a way to get to
the house).  If your yard has too many trees near the martin housing, relocate
the system to a more open area, mount the housing higher, or prune (or
completely remove) trees to create a more open site.  If you have a wooded lot,
but live near a body of water, then boat docks make ideal locations for
mounting purple martin bird houses.  We've also mounted them on top of
buildings and off of deck railings with excellent colonization results.
Purple Martin Housing System Placement
Photos Courtesy of PMCA
For $30, Purple Martin Propagators will come out to
your site (must be within 40 miles of our base or fuel
cost will apply) to check on the required clearances
for installing a purple martin housing system.