In the United States, there are approximately 57 million pet cats that spend at least some time outdoors.  These outdoor cats pose a significant risk to wild birds and small mammals.  It has been estimated that approximately 1 billion birds die annually from cat predation in the United States alone.  To reduce cat predation at your bird feeders, try the following tactics. 

1. Move bird feeders away from hiding places - Move feeders away from objects where cats may hide or alternatively move these objects.  This should reduce the element of surprise that cats have, and reduce their ability to sneak up on birds.
 
2. Consider switching the bird seed in your bird feeder - Often times birds will push unwanted seed in a feeder to the ground.  In turn, birds that use this seed feed on the ground and are more vulnerable to cats.  Watch your bird feeder, and see if there are certain foods that the birds are dropping to the ground.
 
3. Consider changing bird feeders - Some bird feeder types are more likely to have seed fall on the ground than others.  For example, on windy days, bird seed from platform feeders can readily spill to the ground.  A feeder less likely to lose bird seed may reduce the amount of seed falling to the ground.
 
4. Consider a mat under your bird feeder - If switching foods or feeders is not practical, consider placing a mat under your bird feeder.  As food builds up, you can dispose of the seed on the mat, reducing the number of birds that will congregate under your feeder.