Corvids - crows, jackdaws and magpies - are clever and strong, and they can easily intimidate the smaller birds into forfeiting their meal. Our Simon King Medusa Feeder Defender is designed to keep these larger birds at bay with chains that create discomfort against their flight feathers. Alternatively, our weight-activated feeder senses when a hefty visitor lands and temporarily restricts access, giving the little birds a fairer share of the food.