I noticed several people had mentioned in a post about wanting Martins but not attracting any.
1> think apt building not house.
2> think about animals that prey on Purple Martin chicks, such as snakes and racoons.
a-the apt building will need to be 15 ft or so in the air and free of obstructions but within a 100 feet of human habitat.
b- the ground will need to be free of bushes where snakes could hide
c-pole needs a guard to prevent predators from climbing
3> decoys are nice to attract the teenage Purple Martins looking for a new apt building. The older males will go back to last year's nest
4> when older males want to attract other younger males because there is a vacant apt they fly high in the air and sing a morning song starting about an hour before day break. This song has been recorded and tapes are available.
5> entrance should be starling proof
6> too late for most this year but look in a reference book when purple martins arrive in your area and be ready to attract the younger males who are looking an apt in which to nest and atrract a female
Hope this helps