Communication is key, especially in the animal kingdom. The proprietary blend of predator urine in our PredatorPee® FeederScentry includes an enhanced concentration of the specific organic compounds that activate a squirrel's innate alert system. Birds use sight, not scent to detect things in their environment, so FeederScentry has no effect on them at all. When you use PredatorPee® FeederScentry squirrel repellent around your bird feeder, the birds come to eat and the squirrels do not. All is well. This natural squirrel deterrent comes in a 12 ounce squeeze bottle.