Starling-resistant entrance holes may be used to keep starlings out. If other birds attempt to take over empty martin housing, temporarily block entrances with door stops or paper cups and then put up appropriate, single-unit housing elsewhere in the yard. Once these birds have accepted the new housing, reopen the martin housing. Remember that housing should always be closed up or stored inside for the winter to prevent wasps, squirrels, or other birds from claiming the house before the martins return. Housing Houses that are white or light in color seem to attract martins best.
White houses reflect heat and tend to keep the nestlings cooler.
Larger compartments are better and offer greater protection from predators and elements. Door plugs for these holes can be helpful when closing a house for the winter. Because successful purple martin management often requires access to martin housing, it is best to purchase a house that may be raised and lowered vertically. Access may be required for competitor nest removal or periodic nest checks. Nest checks will not cause martins to abandon their nests and can help in identifying predation.