Whole peanuts in the shell are one of the greatest treats you can offer birds. It's been well publicized that jays and woodpeckers love them, but there are many other species that also enjoy them.
People who feed whole peanuts in the shell to birds often report that after a while of offering them, the jays start calling to each other the moment the peanuts are brought to the feeder. Actually, screaming would be a better description! Once the alert has gone out, the jays literally dive-bomb for their favorite treat, sometimes taking more than one at a time. They then fly to the nearest branch, hammer them open and devour them as quickly as possible so they can return for more.