Elaine, that's really interesting ... I've never had a problem with the WP's chasing off other birds; if a WP is at a feeder it usually takes off when another bird lands.
I'm glad the Grackles are spending the summer somewhere other than my yard.
I saw enough of them at our Daytona house to last me a lifetime; they would arrive in hordes from trees where they nested across the waterway and empty the feeders within 30 minutes!
Yes, September in Florida; hot and .... sticky humid.
I hope we get some relief before long; the newspaper this morning reported that the entire U.S. will see a warmer fall. I promise not to be moaning about the cold when January and February get here.