I regularly feed the birds in my yard and, I know that the biggest pests in my garden are the squirrels. Squirrels enjoy eating bird feed and, scaring away the birds. If you have a feeder, then proofing for squirrels is necessary if you want your birds to carry on coming to your garden.
With a bird feeder, proofing for squirrels is done by enclosing the entire feeder in a wire cage with small openings like chicken wire. The openings let the birds in but, not the squirrels. This can make the feeder look awful and possibly reduce your enjoyment.
Instead of altering the bird feeder, proofing for squirrels can achieve the same results, by moving the feeder. Moving it somewhere which is uneven or, where the squirrels can't easily jump on to the feeder, the squirrels will go elsewhere to look for food.
You can also change the bird feed which will stop the squirrels from attacking. Firstly, squirrels have an irresistible temptation to gnaw through wood and plastic, so choosing a bird feeder that is constructed of wire is best. Also, look for bird feed that is designed to taste awful to squirrels. This won't stop them when they initially taste it but, it will send a strong enough message to ensure they don't come back.
So that you can enjoy your garden and the birds, you must make sure that you scare the pesky squirrels away on every occasion that they visit so that the birds aren't tempted to fly to someone to elses back garden.