Bluebird feeder styles range from dish-style or bowl style to the predator-resistant, house-style feeders where the bluebird go inside the bird feeder through a hole on each side. This provides protection for the bluebirds from predators. Their feeder food favorites are mealworms and small pieces of fruit or berries, including raisins. When insects and other natural food supplies are less available, they will also eat small peanut and sunflower kernels, as well as suet.