Last year my neighbors rose bush housed around 6 pairs of House Sparrows and they would visit my Martin House everyday....
Took about 4 consecutive afternoons and some .25cal Hades to get rid of them.
If you are a Purple Martin Landlord having a way to get rid of these pest birds is key to having a PM Colony every year!
I have only had 2 Pairs of House Sparrows visit the house this year so maybe they got the message haha!