A Purple Martin House needs to have several apartments which makes them too heavy to ship. I made one that was 37lbs! They like to habitat together. If you are near water, thats a plus because the martins eat mosquitos and flying insects, but water is not absolutely necessary. Each apartment must be 6″ x 6″ and plenty of ventilation. I make them by order. Holes are 2 to 2.5 inches for each apartment 1.5 – 2″ above the floor. They also love to sun themselves so I add a shelf under each hole. The hardest part is mounting a large house like this 12 – 15 ft above the ground. It also needs to be cleaned out. I have seen break away poles on line made so you can mount them high but break down for cleaning and they are a lot less expensive then I thought they would be.