My father once told me in order to get choice song birds, etc, the key is to
cut the exact correct size hole in the bird house. For example finches, which
come in a variety of colors, will use a bird house with a very small hole.
The sparrows are a little too big for it and will look elsewhere.

I used to keep the small birds around by feeding them Wal-Mart bird seed from
mid winter well into the spring. The bigger birds come too as there isnt much
to keep them away, but the small ones will hang around longer if there is
steady food source.  Feeders are available for the smaller ones. We had what
I called a hive of Martins in multiple floor bird houses. More like apartment
buildings on tall poles.
Bill A