I solved my squirrel problems by getting a squirrel feeder. I get extra peanuts in-the-shell to add to the "critter crunch". The squirrels take the large peanuts and bury them. They spend up to 15 minutes per peanut which means they will have less time to harrass the birds...I also found that the scratching they do helps aerate the soil and the grass grows bushier. Plus, the seeds they drop onto the ground draws J's and Doves.
So, along with the squirrels, J's, and Doves, my thistle socks and sugar dispensers draw a full range of finches and hummingbirds. And, the peanuts draw magpies during the summer. I get so many birds and such a variety in my yard that a hawk will occasionally fly over to see what's for lunch and once a month or so there's evidence of a frag.