Feeding crows

I have been regularly feeding local crows. I leave scraps and chicken and other bones out on a plate. The crows usually find it quite quickly but once the scraps were raided by a local cat before the crows got there.
There seem to be several families around now. One crow waggled its wings as I have seen the young sparrows do when they want to be fed. The adult crows simply ignored this behavior. The crows even come and feed on the sunflower seeds below the feeder sometimes. I have also put out a dish of water for the crows and other birds to drink from. The crows use it regularly. I have to inspect it regularly to make sure that mosquito larvae are also not taking advantage of the water!