Poles that allow the housing to be lowered
Do not buy or build a house that you can’t raise and lower easily. If you can’t check your houses at least once a week, eventually you will have problems and the Martins will suffer. The housing unit must be capable of being easily and quickly lowered or raised by the owner without disturbing the eggs or young birds. Anyone reasonably healthy should be able to use a house fitted with a rope and pulley. A house raised or lowered with a winch should be accessible to all but the most severely disabled persons. Telescoping poles require more strength and agility to use.
Compartments that open for inspection
Whether you have a traditional house or gourds, you must be able to easily check the inside of each compartment. Houses should have doors that can be opened and closed easily and quickly. Gourds should have some means of access large enough to put your hand in. Starlings, Sparrows, and snakes may invade compartments and need to be removed as quickly as possible. A young bird can die and if not removed can contaminate an entire nest. An egg may fail to hatch and if not removed can break and attract flies which will then attack nestlings. Doors that access individual compartments are best. Those that access two or more compartments at once are less desirable. If a house does not have a door that will allow you to open it easily and put your hand in the nesting area, don’t buy it.
Good drainage and ventilation
It is highly advisable (in Southwest Florida it is virtually necessary) to provide owl/crow guards to keep those predators from decimating the colony. Only a few houses on the market have commercial owl/crow guards that can be purchased as add-ons. All the rest have to be built and added on by the owner. In addition to owl/crow guards on the house to deter flying predators, it is important to have some type of predator guard at the base of the pole to ward off snakes, cats, raccoons, squirrels and any other bird-eating predator in the area. Snakes can and do easily climb poles and putting grease on them only lets you see the tracks they’ve made as they went up to raid the house. There are commercial predator guards available on the market that look like a 3′ piece of stovepipe suspended from a solid circular piece of metal at the top. The base of the pipe is loose and moves toward the pole as a cat or raccoon tries to climb it (put it high enough so they can’t jump to the top of the guard and climb the pole from there.) Innovative landlords who are handy with tools can devise and put up their own predator guards made from 6” or larger stove pipe, PVC pipe, etc.
Martins love to have places to perch and watch their house. Telephone or electric wires in the area of the house are great and TV or ham radio antennas also are often used. Commercial perches that can be clamped on a galvanized pipe are also available. Most houses are sold with some sort of perch on top and landlords often add more or longer perches in order to accommodate more birds. Perching areas of any kind definitely are a help in attracting martins to a colony.
Purple Martins are cavity nesters and do not need porches but perching predators, such as crows, find them very handy. All commercial houses available today come with porches, even though they are neither necessary nor desirable. If the porches can’t be removed without doing damage to the house structure, landlords should place dividers between compartments to dissuade males from trying to claim more than one compartment and to keep young birds from wandering into the wrong compartment. Gourds do not have porches and they should not be added unless Snyder Excluder entrances are used. Canopies can be placed over gourd entrances to help keep out rain. A rough texture on the canopy can serve as a perching place for Martins if it does not provide help to predators.