My birds shit mainly on paper, so none! All.kidding aside.. my wild birds did a great job last year moving seed from the feeders. The entire garden was inundated with wild sunflowers and millet.. both played pivotal roles in feeding both birds and bees. It was a trip. Maybe hundreds more bees this last season than previous and at any given time we had at least a dozen doves mixed in with dozens of sparrow and finch, Jay's and cardinals joined in as well, we even got a flock of brown-headed cow birds. Eclectic yardage is so much more fun and healthy than just useless grass.