But there's always a price for human interference in the way of Nature. I seem to have provided an ideal place for the Dove to "increase their number" - exponentially. Now there are more and more of them, and since they are large birds, they muscle the others off the feeding area and eat 5 times what the others would.
I also get a fair number of Brown-headed Cowbirds, a European import that lay their eggs in native songbird nests. Not a good thing, but my Bluebirds and Flycatchers seem to cope without any help from me.
I've decided not to engage in defensive tactics or get myself bent out of shape trying to keep some birds away while welcoming others. So I just close the curtains and let them get on with it. At least I'm providing food and water to some animals that might not get it otherwise.