Squirrels are smart and sneaky. They easily enjoy more of the seed left out for birds than the birds do. Setting up a bird feeder will automatically attract squirrels as well as birds. Keeping squirrels away from the feeders is not easy. There are several "squirrel-proof" bird feeders on the market that claim to deter squirrels. Spinning feeders are one type of squirrel-proof feeders.
Droll Yankees, a feeder store since 1969 according to its website, sells a squirrel-proof spinning bird feeder called the Yankee Flipper. It is a tube feeder with a built-in motor. When a squirrel tries to climb on the feeder, the weight will trigger the motor. The feeder will begin to spin and throw the squirrel off. The feeder is set to spin at a specific weight. Anything lighter, and it will not run. This protects lightweight birds, allowing them to sit on the feeder and eat. The tube also helps deter squirrels. If a squirrel tries to jump on the top of the feeder, it will slip down the tube, grab the perch and set off the motor.
The SquirrelStop Automatic Spinning Squirrel Deterrent, made by Contech, turns any bird feeder into a spinning squirrel-free bird feeder. It is a dome with a built-in motor. A hook dangles from the bottom. Attach any feeder to the hook, and set-up is complete. When a squirrel jumps on the feeder, the weight triggers the motor in the dome. The dome spins and spins the feeder with it, while throwing the squirrel away from the seeds. The SquirrelStop is weight-sensitive and spins only at a certain weight. Birds that are naturally lighter than squirrels do not set off the motor.
The Rollerfeeder is a nonmechanical squirrel-proof bird feeder. It requires no batteries. The feeder has a stationary container for seed. Around the container is a rotating cover. When a squirrel tries to jump to the feeder, it spins from the squirrel's weight. The unexpected spin makes the squirrel fall. If the squirrel jumps from a distance, the feeder spins fast. If the squirrel climbs over to the feeder, the weight still spins the feeder, and the squirrel dangles from the bottom until it falls off.
Most spinning squirrel-proof feeders require batteries to run the motor, which need to be replaced regularly. The motor will stop running over time, especially if subjected to harsh weather. Just because the feeders claim to be squirrel-proof does not mean a squirrel will never figure out how to get the seed. Some do manage to hang on while spinning, until the battery or motor dies. Large birds that eat well may set off the motor. The motorised feeders spin fast and throw the squirrel, or fat bird, far distances. They can, and do, injure the animals.