No bird feeder is 100% predator-proof, but this grid-like design is one of the most effective we've tested for keeping aggressive blue jays and wily squirrels at bay. Developed with the British Trust for Ornithology, this feeder's epoxy-coated steel globe lets birds perch safely inside while keeping predators out. The rugged design assures a long life of year-round service. Fill the polycarbonate feeding tube with 14 oz. of sunflower or wild-bird mix.