They hunt for mental stimulation, not hunger, and will kill prey and not consume it. It is the responsibility of cat owners to ensure that their cats are kept happy and healthy and away from the birds. A feeder that is too low to the ground or too close to bushes and trees provides an excellent ambush spot for the patient cat who sees the feeder as a buffet line. Bell your cat. Hinder maternal instruction.
Kittens learn from the example set by their mothers.
Female cats with a litter are often the most aggressive hunters. By preventing the mother to bring prey to the litter, you can reduce their hunting interest. The best solution however, is to spay or neuter your cat to prevent the numerous unwanted litters born each year. Keep your cat inside. The best way to protect your birds and wildlife is also the best way to protect your feline friend.