Rain and 4 of the 6 hummingbird feeders get runoff from pressure treated lumber on 2nd floor porch. Luckily squirrels haven't decided hummer feeders were worth exploring. Could be because they're so fat from all the bird seed...especially sunflower. I feed already hulled sunflower to avoid the mess and allelopathic effects from hulls. Also, I'm wondering if it will help with ants