house sparrows are an introduced (exotic) species in america. nevertheless, they are the most populous songbird species with an estimated population exceeding 150 million. house sparrows compete aggressively with the native bluebirds for resources. many studies blame the decline in bluebird populations on house sparrows. in the reauthorization of the migratory bird treaty act, clarification was added stating that invasive, exotic species are NOT federally protected. hence, states can now add language to their own statutes regarding control of exotic bird species. the audubon society and the bluebird recovery program are pushing minnesota to include the house sparrow in the invasive species category and change the wording of its statutes to say that not only is it illegal to introduce exotic species, but also to release them. This would make it illegal to rehabilitate wild caught injured and orphaned house sparrows and release them back into the wild. last year, the general public brought approximately 1000 house sparrows to the biggest rehab center in Minnesota; of those barely half were released back to the wild.