Cayenne pepper is one of the things you can use to deter them. Here are some tips on how much cayenne pepper to put in your bird seed: nn-Start with a small amount of cayenne pepper and gradually increase it until you find the right amount that works for your situation. n-The amount of cayenne pepper you'll need to use will vary depending on how squirrels are getting to your bird feeder. If they're climbing up a tree, for example, you'll need to use more pepper than if they're just digging under your fence. n-Cayenne pepper won't hurt the birds, but it will make the seed less attractive to squirrels. If you're concerned about squirrels raiding your bird feeder, give cayenne pepper a try.