Northern Rough-winged Martins?

Some of our local Rough-winged Swallows seem to think they are in England, where the small, brown members of their family may also be granted the title of "martin." At least, they have felt free to move into the new martin house I built and installed this spring. As no Purple Martins have decided to start using the house yet, the Rough-wings are welcome to it. They swoop and dive around the orchard most charmingly themselves, even if their voices are not quite so other-worldly and musical as their big cousins. Maybe they will even attract the attention of some of the intended occupants.

I built the house with those new-fangled crescent-shaped, floor-level "Starling-resistant Entrance Holes." And I have been very impressed. I have several times watched Starlings attempt without success to enter the house. Just as satisfying, the House Sparrows have gone in to the apartments, investigated, and then left without making use of them. Perhaps the floor-level entrance does not work with their style of nest building?