You can try mixing cayenne pepper with the seed to repel the mice but it might affect the birds by getting the pepper dust in their eyes.

I better idea is to install a seed catcher below the feeder so that seeds don't fall. Make sure to rake up any that do hit the ground.

Are you storing the seed in a metal container to keep out the mice?

Wild Birds Unlimited sells a package mix of cayenne pepper and who knows what all else. Many people use straight cayenne pepper. It doesn't hurt the birds or get into their eyes at all. It repels squirrels and coons from my understanding. So it might work on mice. You have nothing to lose at this point!

The best thing would be to find where the mice are getting in at and plug those holes. A metal container is good too, but plug up those holes! âº