Sparrow wars

I'm waging a war against sparrows. Not sparrows in the Embirizidae family, the mysterious stripey ones who hide in bushes and live in rural areas. I'm annoyed by the one Passeridae sparrow that lives in the US: the House Sparrow. This one is not native and has taken over habitats, to the detriment of other birds. I know I should like all birds, but I only like House Sparrows when they are the only ones around. Unfortunately, this happens a lot in my suburban home :( My mother-in-law has two bluebird boxes up. The sparrows are determined to steal them, so I am determined to steal them back! It is unlawful to disturbe bird nests, but House Sparrows are not under this protection because they are considered introduced and nuisance birds. (Wouldn't it be fun to be on the committee who labels things "nuisance"?) My goal is to keep an eye on the boxes and remove nests built by the sparrow. The nest built by the bluebird has different materials and a different shape than that built by the sparrow. I was taught this by a lady who kept up a lot of bluebird boxes on her extensive property. The eggs of the sparrow even look different, and she's removed them too, in order to give the bluebirds a chance to jump in. One time she was late checking and sparrow eggs had hatched. She didnt have the hear to hurt the nestlings! A sparrow's nest is constructed with a crazy assortment of materials, like stickes, grasses, feathers, trash. The bluebird uses almost exclusively sticks, and they are all similar in size. The sparrow nest uses more space in a birdbox. It piles up the back and top, sometimes coming over far enough to make a tube to go down to where the eggs are. A bluebird confines his nest to a regular bowl shape in the bottom half of the box. If I see the starts of a sparrow nest, I will remove it and throw it in the trash. If I toss it on the ground, the birds will just transfer it back to the box and I wont have slowed them down enough! I hope the sparrows get so frusterated they nest somewhere else! I hope the bluebirds are ready to move in at the first chance!