Do you hang your bird feeders from poles or tree branches? I hang mine from tree branches and use a "baffle", or plastic cover that you hang the bird feeder under. It swings freely above the feeder, and the squirrels just slide off if they attempt to get to the feeder, but they still have access to the seed that falls on the ground. You can get them anywhere they sell bird feeders.
If you have platform feeders, change to safflower seed; most squirrels don't eat that particular seed.
I've got them on shepherd's hooks. Our Wild Birds Unlimited recommended the baffles as well. I just haven't purchased them.
The bees drank all my hummingbird food. Never saw a hummingbird.