May work to just put the food under a feeder with a roof. It is a matter of getting the food to the birds you want by making the setting the food is in OK for the birds you want and not OK for the others. So the combo of openness, mesh to size filter, covers etc has to be changed.
Our garden is open to countryside and there are lots of rooks, crows, pigeons, kites and hawks around here. We now don't feed the small birds as we either get other birds taking the food or taking the small birds.
We did have lots more crows a few years ago but seem to have less now the Kites are very well established.