The bluebird and flycatcher nest throughout much of the martin's range while the Tree Swallow nests largely in the northern areas of the martin's breeding areas. Since crested flycatchers are largely forest birds, they typically are not that much of a problem for martin housing placed in very open areas. However, bluebirds and Tree Swallows are readily attracted to many types of housing placed in open areas, with Tree Swallows most attracted to areas with a body of water nearby. It is important to understand that native birds become a potential problem only at new colony sites where martins have never nested before. Martins which have not established nesting territory are not aggressive and are easily driven away by other nesting birds.
Native competitors are almost never a problem at colony sites where martins are already nesting.
Tree Swallows or crested flycatchers which may show an interest in the housing. These native hole-nesters rarely try to fight their way into an established martin colony. Once martins have bred successfully, they become very attached to the housing and will vigorously defend their territory. Even if a bluebird or Tree Swallow has setup territory at an established site before the martins arrive, the returning martins will quickly regain their housing. The bluebird or Tree Swallow will be driven out.