Many birds are attracted to this type of feeder but there are a few drawbacks, depending on your viewpoint: Hopper feeders generally do not keep squirrels away, so be prepared to feed the squirrels along with your favorite birds. Also, while hopper bird feeders can protect seed from weather and keep it cleaner, there is the possibility of the seed getting wet because hopper feeders seldom are waterproof. Most hopper feeders can be mounted on a post or hung from a tree branch or a hanging hook on your patio.