Hi Caron, is the feeding station out in the open or near to trees and bushes?
If it is out in the open you may want to move it as many small wild birds prefer to have natural cover near to their feeding area.
Placing your station near to some good cover such as some bushes or trees will make the station a much more desirable prospect.
What food are you putting out on offer? Based on the birds you have had visiting it sounds like there may be high wheat content in a mix that you are offering, though this is just speculation :)