House sparrows have now murdered 2 bluebirds (one last year and a male over the weekend) and a tree swallow last year. Any suggestions on control of this. I remove sparrow nests daily from all my boxes and over the weekend bought a sparrow trap. However, a female bluebird got caught in the trap- so not so sure that the trap will work. I am converting the boxes to slot openings since it seems as if the bluebirds will use the slot boxes and the sparrows do not. (Plus I heard the the slot boxes do allow the bluebirds to escape if a sparrow tries to attack them). Any other suggestions?