Hi Swan - Congratulations on having a local woodpecker visit and be safe in the knowledge that teh cats will not kill it butu neither will it touch bird food.
The green/yellow ones feed on ants in the ground and mostly in the lawn. They won't eat anything you provide and are obviously dodging the cats quite well already.
If you put a feeder up for the bluetits and sparrows etc, hang it away from anything that a cat can climb up and you'll be fine. They can wait underneath it all they like but they'll never catch the birdie!



