One successful predation attempt by any of these predators can, and usually does, mean that your martin season is over, not only for the current season, but for the future. Surviving birds go elsewhere in future seasons. Typically, it takes much patience and work to successfully attract martins today. By providing our martins with enlarged compartments, we are helping to protect them from Horned and Barred Owls, however, we should also provide a ground climbing predator barrier to keep the remaining enemies from accessing the martin house and its valued contents. By providing a martin house, there is an accompanying responsibility to protect them so that they do not become easy meals for their enemies.
Martins like to perch on old tree snags, TV antennas, and utility lines.
If there are none of these in your area, you should try to provide either an old TV antenna or extra perches attached to the martin house or pole. I have attached them to the underneath of the porch floors on Trio TG-12 houses providing an additional 8 more feet of perching space in addition to the roof perch. I can help you with this. Typically, after one season where the martins are bonded to your house and colony site, they will go through these new openings easily. All martin houses should be painted white.