Near my house, I have set up a birdhouse, which has become home to a pair of Oriental Magpie Robins. They are not a common species in Delhi, India, and are generally shy of human interaction and avian conflict (territory disputes with other species):
However, the birdhouse is constantly visited by a pair of Common Myna. This bird is notorious for being an invasive species and had chased away a pair of Oriental Magpie Robins in the past.
Is there some way for me to get rid of the Mynas without scaring away the Oriental Magpie Robins? The bird is a real menace and I'm afraid it'll push away the Oriental Magpie Robin and other species of smaller birds that visit my locality. It is already considered an invasive species in Australia and South Africa. I don't want to kill the Myna, and trapping is out of the question as well. I just want to scare it off or restrict access to the birdhouse. Is there some way to make the birdhouse and surrounding area more appealing to the Oriental Magpie Robins?
Update: The Mynas seem to be guarding the bird house from a distance, since I have been shooing them away. The Oriental Magpie Robin hasn't showed up since.